Dynamic double network shear thickening protective material and preparation method thereof

Abstract

The application discloses a kind of dynamic double-network shear thickening protective materials and preparation method thereof, it is related to the technical field of protective function polymer material;The material has double continuous interpenetrating polymer network structure, including three-dimensional continuous physical shear thickening network and three-dimensional continuous covalent crosslinking chemical network which are mutually penetrated and entangled, the dispersed phase area of two phases under 5000 times scanning electron microscope is less than 100nm, the interface between two networks is combined by non-covalent bond, so that nano-particle can be freely sheared and induced to aggregate, while inhibiting sedimentation and cold flow;Double-network dry mass ratio is 5:1~10:1, double-network interpenetration degree is 40%~70%, and crosslinking density is 1×10⁻⁴ mol / cm³~5×10⁻⁴ mol / cm³;The application also provides intermittent and continuous preparation methods, and impact protective products comprising the material.The application breaks through the technical prejudice in the field, solves the problem that the protective performance and stability of existing materials cannot be considered, and is suitable for various impact protection scenes.

Description

Technical Field

[0001] This invention relates to the field of protective polymer materials technology, specifically to a dynamic dual-network shear-thickening protective material suitable for human protection, industrial buffering, explosion-proof and impact-resistant applications, and its preparation method. Background Technology

[0002] Shear-thickening fluids, with their adaptive properties of "normal flexibility and instantaneous hardening upon impact," are widely used in fields such as personal protective equipment, industrial cushioning, and explosion-proof and impact-resistant applications. However, existing purely physically dispersed shear-thickening fluids generally suffer from core defects such as easy sedimentation and stratification after long-term storage, severe cold flow phenomenon, narrow temperature range, and poor stability during cyclic use. They are also prone to solidification at -40℃ and their shear-thickening performance degrades by more than 50% at 80℃, failing to meet the long-term use requirements under complex working conditions.

[0003] The closest prior art: Publication number CN115386340B, IPC classification number C08L75 / 04, publication date December 6, 2022, discloses a discontinuous shear thickening fluid and its preparation method. It uses nano-silica particles dispersed in a polyethylene glycol dispersion medium to form a purely physical dispersion system. The shear thickening performance is improved by controlling the particle size and surface modification of the nanoparticles. The core drawback of this approach is that the purely physical dispersion system lacks structural support, resulting in a cold flow rate of 8.72%. Significant sedimentation and stratification occur after 3 months of storage, and the performance decreases by 22% after 100 cycles. It fails to address the long-term sedimentation and cold flow issues.

[0004] Prior art 2: Publication number US11230728B2, IPC classification number C08J3 / 24, publication date January 25, 2022, discloses a cross-linked shear thickening material. It employs a single cross-linked network structure, dispersing nanoparticles within polymer monomers and forming a chemical cross-linked network through free radical polymerization, encapsulating the nanoparticles within the network. The core drawback of this approach is that the chemical network is a discontinuous phase, restricting the free movement of the nanoparticles and resulting in a shear thickening factor of only 85 times, significantly reducing its protective performance.

[0005] As of the filing date of this application, there has been a long-standing and widely accepted technical bias in this field over the past 10 years (from January 1, 2014 to the filing date of this application): continuous chemical cross-linking structures restrict the free migration and shear-induced aggregation of nanoparticles in shear-thickening fluids, irreversibly destroying the shear-thickening response characteristics and resulting in a significant decrease in protective performance. Therefore, high-performance shear-thickening protective materials must adopt a purely physical dispersion system and absolutely avoid introducing continuous chemical cross-linking networks.

[0006] I. Evidence regarding the prevalence and generally accepted nature of this technological bias: The complete publication information of the authoritative review article in this field is: Acta Polymerica Sinica, Vol. 5, 2021, pp. 487-498, "Research progress on the rheological behavior and protective applications of shear-thickening fluids". This article is a top authoritative review in this field. As of the date of this application, it has been cited 237 times in the CNKI database. It clearly states that "continuous chemical cross-linking networks can limit the shear-induced aggregation of nanoparticles, leading to a significant decrease or even disappearance of the shear-thickening effect". This view has been directly cited by 37 subsequent core journal articles in this field, forming the mainstream understanding in this field.

[0007] The common technical choices of mainstream commercial patents in this field: Paragraph 0004 of the background technology section of the specification of the authorized invention patent CN115386340B (the mainstream commercial solution in this field, the product has been mass-produced and launched) clearly states that "chemical cross-linking will encapsulate nanoparticles, destroy their fluidity, and cause a significant decrease in shear thickening performance. Therefore, existing high-performance shear thickening materials all adopt a pure physical dispersion system without cross-linking"; Paragraph 0003 of the specification of the authorized invention patent CN112143567B (the core improvement solution in this field) clearly states that "chemical cross-linking structure will destroy the shear response characteristics of shear thickening fluid, and high-rate shear thickening cannot be achieved".

[0008] The general abandonment of research directions in this field and the time frame: As of the application date of this application, through the patent search and service system of the State Intellectual Property Office, using the search terms "shear thickening and protective materials and authorized invention patents and application date between January 1, 2014 and the application date of this application", a total of 127 authorized invention patents were retrieved. Among them, 125 patents adopt pure physical dispersion systems without chemical crosslinking, and only 2 patents adopt island structures with discontinuous chemical crosslinking. None of them disclose a technical solution combining a dual-continuous interpenetrating network with a shear thickening physical network. Meanwhile, through the CNKI and Web of Science Core Collection databases, using the search terms "shear thickening + dual-continuous interpenetrating network + chemical crosslinking", with a search time frame from January 1, 2014 to the application date of this application, no published core journal articles or patent documents were found that applied a dual-continuous interpenetrating network structure to shear thickening protective materials and improved shear thickening performance while introducing a continuous chemical crosslinking network. The above search results demonstrate that researchers in this field have generally abandoned this technological direction over the past 10 years, forming a recognized and long-standing technological bias in the field.

[0009] This technological bias is not a scattered perception in the field, but rather forms a complete mainstream technological orientation: the research and development of all high-performance shear-thickening protective materials in this field focuses on the formulation optimization of pure physical dispersion systems, completely abandoning the technical direction of improving material stability through continuous chemical cross-linking structures. No published patent or core journal paper has successfully achieved the technical solution of "introducing a continuous chemical cross-linking network while improving shear-thickening protective performance".

[0010] II. The core reason why this technological bias deviates from objective facts: The prevailing understanding in the current technology is that continuous chemical cross-linking networks will encapsulate nanoparticles, restricting their shear-induced aggregation behavior, which will inevitably lead to a significant decrease or even disappearance of the shear thickening effect. Therefore, high-performance shear thickening protective materials must adopt a pure physical dispersion system and absolutely cannot introduce continuous chemical cross-linking networks.

[0011] The core reason this perception deviates from objective facts lies in the fact that all existing technologies involving chemical cross-linking employ a "sea-island structure" where a chemical cross-linking network is first formed, followed by filling with a shear-thickening fluid. In this structure, the chemical cross-linking network is the only continuous phase, while the shear-thickening system is the encapsulated dispersed phase. This inevitably restricts the free movement and shear-induced aggregation of nanoparticles. In contrast, this application pioneers a dual-continuous interpenetrating network structure. Both the physical shear-thickening network and the covalently cross-linked chemical network are three-dimensional continuous phases, interpenetrating and entangled without any encapsulation relationship. Nanoparticles can move freely and undergo shear-induced aggregation within the continuous physical network, completely unrestricted by the chemical network. Instead, the shear-thickening effect is enhanced through interfacial bonding. The prevailing understanding of existing technologies is completely inapplicable to the technical solution of this application, thus forming a long-standing and widely accepted technical bias in the field, deviating from objective facts.

[0012] The aforementioned technological biases directly hinder research and development in this field. None of the existing technologies offer the technical insight that "by combining a bicontinuous interpenetrating network structure with intermolecular forces at the interface, the shear thickening performance can be improved while introducing a continuous chemical cross-linking network." Instead, they provide explicit negative guidance, preventing researchers in this field from exploring this direction. There are no successful examples of combining continuous chemical cross-linking networks with high-performance shear thickening systems in the existing technologies. Existing shear thickening protective materials generally face the core technical challenge of simultaneously achieving high shear thickening protective performance and long-term structural stability. There is an urgent need for a dynamic bi-network shear thickening material that can simultaneously achieve ultra-high shear thickening ratios, extremely low cold flow rates, wide temperature range adaptability, and excellent cycling stability. Summary of the Invention

[0013] I. Definitions of Relevant Terms The definitions of all technical terms in this specification are their sole meanings in this application and are used to interpret the scope of protection of the claims.

[0014] The dual continuous interpenetrating polymer network structure described in this article refers to a polymer system in which both the physical shear thickening network and the covalent cross-linked chemical network are three-dimensional continuous phase structures, interpenetrating and entangled with each other, without phase separation. The absence of phase separation described in this article means that when observed with a scanning electron microscope (SEM) at 5000x magnification, there are no obvious phase regions on the cross-section of the material, and the maximum size of the dispersed phase regions of the two phases is less than 100nm.

[0015] The reversible dynamic cross-linking network described in this article refers to a cross-linking network formed by intermolecular non-covalent bonds, in which the cross-linking bonds can undergo reversible breakage and reconstruction under shearing action.

[0016] The dry mass ratio mentioned in this article refers to the ratio of the dry mass of nanoparticles in the physically shear-thickened network to the dry polymer mass of the covalently cross-linked chemical network. The method for determining the dry mass ratio is as follows: Soxhlet extraction with toluene combined with muffle furnace ignition. The specific steps are as follows: the sample is cut into uniform fragments of 1 mm × 1 mm, extracted with analytical grade toluene using Soxhlet extraction for 72 h to completely remove the uncross-linked soluble components, and vacuum dried to constant weight at 60 °C and a vacuum degree ≤ -0.095 MPa to obtain a mixture of insoluble covalently cross-linked chemical network dry gel and nanoparticles; the mixture is then ignited in a muffle furnace at 600 °C for 3 h to completely remove the organic polymer components, and the remaining constant weight is the dry mass of the nanoparticles; the dry mass of the covalently cross-linked chemical network = constant weight of the mixture - dry mass of the nanoparticles; the dry mass ratio = dry mass of nanoparticles / dry mass of the covalently cross-linked chemical network.

[0017] The interpenetration degree of the dual networks described in this paper was tested using dynamic mechanical analysis (DMA). The test conditions were: tensile mode, frequency 1 Hz, heating rate 3 ℃ / min, temperature range -80 ℃ to 150 ℃, amplitude 10 μm, and calculated using the formula ID = (Tg - Tg1) / (Tg2 - Tg1) × 100%, where Tg is the glass transition temperature of the dual network material, Tg1 is the glass transition temperature of the purely physical shear-thickened network, and Tg2 is the glass transition temperature of the purely covalently cross-linked chemical network.

[0018] The crosslinking density described in this article was tested using the toluene equilibrium swelling method. The crosslinking was carried out at a constant temperature of 25°C for 72 hours until equilibrium was reached. The crosslinking density was calculated using the Flory-Rehner equation, where the Flory-Huggins interaction parameter χ1=0.45, the toluene density ρs=0.8669g / cm³, and the polymer density ρp=1.05g / cm³.

[0019] The shear thickening factor described in this article was tested using a rotational rheometer with a parallel plate fixture. The test environment was 25℃, 50% relative humidity, with a test gap of 1mm, and a steady-state shear rate range of 0.1–10. 4 s⁻¹, shear thickening factor = ηmax / η0, where ηmax is the maximum apparent viscosity at a shear rate of 1000 s⁻¹, and η0 is the zero shear viscosity.

[0020] The polar dispersion medium described in this article refers to at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether glycol, which is a polar polymer medium whose molecular chain contains polar groups and can form hydrogen bonds with the hydroxyl groups on the surface of nanoparticles.

[0021] The functional additives mentioned in this article refer to conventional commercially available additives that do not interfere with the formation of hydrogen bonds between nanoparticles and polar dispersion media and can improve the performance of materials, including but not limited to antioxidants, ultraviolet absorbers, flame retardants, and anti-aging agents. The amount of the functional additive added shall not exceed 1% of the mass of the polar dispersion media.

[0022] The polymer molecular chain mentioned in this article refers to the complete molecular chain of a high molecular polymer that constitutes a covalently cross-linked chemical network, including all segments on its main chain and side chains.

[0023] The alcohol dispersion medium mentioned in this article refers to low-carbon alcohol solvents that can achieve uniform dispersion of nanoparticles, including but not limited to anhydrous ethanol, methanol, isopropanol, etc.

[0024] The non-covalent bonds mentioned in this article refer to non-covalent bond forces that can form stable interfacial bonds, including but not limited to hydrogen bonds, van der Waals forces, coordination bonds, and dipole interactions.

[0025] The polymer modifiers described herein refer to polymers obtained through epoxy, amino, and vinyl grafting, copolymerization, or block modification that retain crosslinkable reactive groups after modification and can form a three-dimensional continuous crosslinked network through covalent bonds, including but not limited to epoxy-modified polyurethanes, amino-modified epoxy resins, and vinyl-modified polysiloxanes.

[0026] The small molecule diol chain extenders described in this article refer to small molecule organic compounds containing two hydroxyl groups in their molecular chains, including but not limited to 1,4-butanediol, 1,3-propanediol, ethylene glycol, 1,5-pentanediol, and 1,6-hexanediol.

[0027] The one-step in-situ synchronous crosslinking method described in this article refers to a process that simultaneously completes the hydrogen bond crosslinking of the physically shear-thickened network and the covalent bond curing of the covalently crosslinked chemical network through a single hot-pressing process, thereby forming a bicontinuous interpenetrating polymer network structure.

[0028] II. Technical problems to be solved The purpose of this invention is to overcome the deficiencies of existing technologies and the technical biases in the field, and to provide a dynamic dual-network shear-thickening protective material and its preparation method. Through a structural design of a dual continuous interpenetration between a physical shear-thickening network and a covalently cross-linked chemical network, coupled with precise control of the dual-network mass ratio, interpenetration degree, and cross-linking density, the core problem of existing shear-thickening materials being unable to simultaneously achieve high protective performance and long-term structural stability is solved. At the same time, it achieves ultra-high shear-thickening ratio, extremely low cold flow rate, wide temperature range adaptability, and excellent cycle stability, breaking through the long-standing technical biases in the field. It also provides two preparation methods, intermittent and continuous, covering the full range of needs from laboratory research and development to industrial mass production. Technical solution

[0029] To achieve the above objectives, the present invention adopts the following technical solution: Product Technical Solution: A dynamic dual-network shear-thickening protective material, comprising a shear-thickening dispersion system and a polymer crosslinking matrix. The shear-thickening dispersion system includes nanoparticles with active hydroxyl groups on their surface and a polar dispersion medium. The material has a dual continuous interpenetrating polymer network structure, which includes an interpenetrating and entangled three-dimensional continuous physical shear-thickening network and a three-dimensional continuous covalently crosslinked chemical network. Both networks are three-dimensional continuous phases that permeate the entire material, without encapsulated or encapsulated island structures. The maximum size of the dispersed phase regions of the two phases is less than 100 nm, and there is no phase separation. The active hydroxyl groups on the surface of nanoparticles in the physically shear-thickening network form interfacial bonds with the polymer molecular chains of the covalently cross-linked chemical network through non-covalent bonds. These non-covalent bonds include at least one of hydrogen bonds, van der Waals forces, coordination bonds, and dipole interactions. This interfacial bonding allows the nanoparticles to freely aggregate under shear stress, while simultaneously inhibiting nanoparticle sedimentation and material cold flow. The dry mass ratio of the physically shear-thickening network to the covalently cross-linked chemical network is 5:1 to 10:1. The interpenetration degree of the two networks in the material is 40% to 70%, and the cross-linking density is 1 × 10⁻⁻⁻⁻⁶. 4 mol / cm³~5×10⁻ 4 mol / cm³.

[0030] Furthermore, the material has a dual-network interpenetration degree of 50%–60% and a crosslinking density of 2 × 10⁻⁻⁻⁶. 4 mol / cm³~4×10⁻ 4 mol / cm³; optimally, the material has a double-network interpenetration degree of 55% and a crosslinking density of 3×10⁻ 4 mol / cm³.

[0031] Further, the polar dispersion medium is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether glycol, or a mixed system formed by the above polyether and functional additives; the functional additives are at least one of antioxidants, ultraviolet absorbers, flame retardants, and anti-aging agents, and the amount added is 0.05% to 1% of the mass of the polar dispersion medium.

[0032] Furthermore, the nanoparticles are at least one of the following: mesoporous nano-silica with active hydroxyl groups on the surface, nano-alumina, nano-calcium carbonate, nano-montmorillonite, and nano-zinc oxide; the nanoparticles are surface modified by a silane coupling agent, and the surface hydroxyl content of the modified nanoparticles is ≥2 mmol / g; the silane coupling agent is at least one of aminosilane, epoxysilane, and vinylsilane.

[0033] Furthermore, the covalent crosslinking chemical network is any one of polyurethane, epoxy resin, polysiloxane, and polyacrylate, or a blend of two or more of the above polymers, or a modified product obtained by grafting / copolymerizing / block modifying the above polymers and blends with epoxy, amino, or vinyl groups, retaining crosslinkable reactive groups and capable of forming a three-dimensional continuous covalent crosslinking network.

[0034] Further, the covalently cross-linked chemical network is polyurethane, formed by curing and cross-linking a polyurethane prepolymer with an NCO mass fraction of 3% to 8% as tested according to GB / T 12009.4-2016 standard with a small molecule diol chain extender, wherein the small molecule diol chain extender is an aliphatic diol with 2 to 6 carbon atoms; the diisocyanate used in the polyurethane prepolymer is at least one of aliphatic diisocyanate and aromatic diisocyanate; the polyurethane prepolymer is prepared by reacting aliphatic diisocyanate with polyether polyol in a molar ratio of 1.8:1 to 2.2:1, and the NCO mass fraction is 3% to 8% as tested according to GB / T 12009.4-2016 standard.

[0035] Furthermore, the material meets the following performance requirements: (1) Under an environment of 25℃ and 50% relative humidity, the steady-state shear rate is measured using a rotational rheometer with a parallel plate fixture, a test gap of 1mm, and a range of 0.1 to 10. 4 s⁻¹, the shear thickening factor at a shear rate of 1000s⁻¹ is ≥260 times, and the shear thickening factor is the ratio of the maximum apparent viscosity to the zero shear viscosity at that shear rate; (2) at 25℃, the cold flow rate under the conditions of 24h test and 1kg load according to HG / T 3871-2008 standard is ≤0.5%.

[0036] Method and technical solution (intermittent preparation): A method for preparing a dynamic dual-network shear-thickening protective material, used to prepare the above-mentioned dynamic dual-network shear-thickening protective material, including the following steps: S1: Nanoparticle surface modification: Nanoparticles with active hydroxyl groups on their surface are modified to obtain modified nanoparticles with a surface hydroxyl content ≥2mmol / g. S2: Preparation of cross-linked matrix prepolymer: Preparation of polymer prepolymers for forming covalent cross-linked chemical networks; S3: Preparation of premixed system: Modified nanoparticles are dispersed in a polar dispersion medium to obtain a uniform shear-thickening dispersion system; S4: Dual-network in-situ crosslinking: The polymer prepolymer, the corresponding curing system, and the shear-thickening dispersion system are mixed evenly, and the dry mass ratio of the physical shear-thickening network to the covalent crosslinking chemical network is controlled to be 5:1 to 10:1. After degassing, in-situ simultaneous crosslinking is performed in one step, that is, through a single hot-pressing process, hot-pressing is performed at 120 to 140°C and 8 to 12 MPa for 30 to 60 minutes, simultaneously completing the hydrogen bond crosslinking of the physical shear-thickening network and the covalent bond curing of the covalent crosslinking chemical network, and simultaneously forming an interpenetrating and entangled dual continuous three-dimensional interpenetrating network structure. S5: Post-processing: After cooling and demolding, the material is cured to obtain the dynamic dual-network shear-thickening protective material; The execution order of steps S1 and S2 can be arbitrary, synchronous, or interchangeable.

[0037] Further, step S1 specifically involves: dispersing nanoparticles with active hydroxyl groups on their surface in an alcohol dispersion medium to prepare a dispersion with a nanoparticle mass fraction of 8%–12%; adding 1%–3% of a silane coupling agent by mass of the nanoparticles; adjusting the pH of the system to 4–5; stirring and reacting at 60–80°C for 3–5 hours; separating, washing, and drying to obtain modified nanoparticles with a surface hydroxyl content ≥2 mmol / g; wherein the silane coupling agent is selected from at least one of aminosilane, epoxysilane, and vinylsilane.

[0038] Further, in step S2, the polymer prepolymer is any one of polyurethane prepolymer, epoxy resin prepolymer, polysiloxane prepolymer, and polyacrylate prepolymer.

[0039] Further, step S3 specifically involves: dispersing the modified nanoparticles in a polar dispersion medium, stirring at 2000–4000 rpm for 1–3 h, and then ultrasonically dispersing for 20–40 min to obtain a uniform shear-thickening dispersion system; the polar dispersion medium is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether glycol, or a mixed system formed by the above polyethers and functional additives.

[0040] Further, in step S4, the degassing process is as follows: degassing is carried out in stages for 10 to 20 minutes under a relative vacuum of -0.08 MPa to -0.1 MPa, and the entire degassing process is carried out under a constant temperature of 20 to 30°C; the staged degassing is as follows: the first stage is degassing for 5 to 10 minutes under a relative vacuum of -0.08 MPa with a stirring rate of 80 to 100 rpm; the second stage is degassing for 5 to 10 minutes under a relative vacuum of -0.1 MPa with a stirring rate of 50 to 80 rpm.

[0041] Further, in step S4, the in-situ crosslinking process is as follows: after degassing, the material is poured into a mold and hot-pressed for crosslinking at 120-140°C and 8-12MPa for 30-60 minutes to complete the one-step in-situ synchronous crosslinking.

[0042] Further, step S5 specifically involves: cooling to room temperature and then demolding, followed by constant temperature curing at 50–70°C for 12–24 hours to obtain the dynamic dual-network shear-thickening protective material.

[0043] Method and Technical Solution (Continuous Preparation): A continuous preparation method for a dynamic dual-network shear-thickening protective material, used to prepare the above-mentioned dynamic dual-network shear-thickening protective material, includes the following steps: S1: Nanoparticle surface modification: Nanoparticles with active hydroxyl groups on the surface are dispersed in an alcohol dispersion medium to prepare a dispersion with a nanoparticle mass fraction of 8% to 12%. 1% to 3% of silane coupling agent by mass of nanoparticles is added, the pH of the system is adjusted to 4-5, and the reaction is stirred at 60 to 80°C for 3 to 5 hours. After separation, washing, and drying, modified nanoparticles with a surface hydroxyl content ≥2 mmol / g are obtained. S2: Preparation of cross-linked matrix prepolymer: Preparation of polymer prepolymers for forming covalent cross-linked chemical networks; S3: Continuous preparation of premixed system: The modified nanoparticles obtained in step S1 and the polar dispersion medium are continuously added to a twin-screw mixer in proportion and continuously mixed at a speed of 2000-4000 rpm for 1-3 hours, and simultaneously ultrasonically dispersed online for 20-40 minutes to obtain a uniform shear thickening dispersion system. S4: Dual-network in-situ continuous crosslinking: The polymer prepolymer obtained in step S2, the curing system matching the type of prepolymer, and the shear thickening dispersion system obtained in step S3 are continuously metered and mixed in proportion, controlling the dry mass ratio of the physical shear thickening network to the covalent crosslinking chemical network to be 5:1 to 10:1; continuous degassing is carried out for 10 to 20 minutes under a relative vacuum of -0.08 MPa to -0.1 MPa, and the entire degassing process is carried out under a constant temperature of 20 to 30°C, with the stirring rate controlled at 50 to 100 rpm during the degassing process; after degassing, the mixture is continuously coated onto the release substrate and sent to a continuous roller pressing production line, where it is hot-pressed and crosslinked for 30 to 60 minutes at 120 to 140°C and 8 to 12 MPa pressure. The hydrogen bond crosslinking of the physical shear thickening network and the covalent bond curing of the covalent crosslinking chemical network are completed simultaneously in situ through a one-step hot-pressing process, forming a dual continuous three-dimensional interpenetrating network structure; S5: Post-processing: The hot-pressed sheet is continuously fed into the cooling section to cool to room temperature, and after being wound up, it is cured at a constant temperature of 50-70℃ for 12-24 hours. After slitting, the dynamic double-network shear thickening protective material is obtained.

[0044] Product technical solution: An impact protection product, the product comprising a protective functional layer, the protective functional layer being made of the above-mentioned dynamic double-network shear-thickening protective material, or prepared by the above-mentioned preparation method; the thickness of the protective functional layer being 0.5mm to 20mm; the impact protection product being any one of sports protective gear, industrial cushioning pads, automotive anti-collision components, explosion-proof and impact-resistant products, police protective equipment, and aerospace cushioning components.

[0045] IV. Beneficial Effects According to the three-step inventive step assessment method stipulated in the Patent Examination Guidelines 2026, this invention possesses outstanding substantive features and significant progress, as detailed below: The closest prior art was identified as the purely physically dispersed shear-thickening fluid disclosed in publication number CN115386340B. This invention belongs to the same field of impact protection technology and solves the same technical problem of "the protective performance and long-term stability of shear-thickening materials cannot be simultaneously achieved". It is the closest prior art. Identifying the distinguishing features and the actual technical problem solved by the invention: The core distinguishing feature of this invention from the closest prior art is its "dual continuous interpenetrating polymer network structure, comprising a physically shear-thickening network and a covalently cross-linked chemical network, both of which are three-dimensional continuous phases. Under a 5000x scanning electron microscope, the maximum size of the dispersed phase regions of the two phases is less than 100 nm. The active hydroxyl groups on the surface of the nanoparticles in the physically shear-thickening network and the polymer molecular chains of the covalently cross-linked chemical network form an interfacial bond through non-covalent bonds. The dry mass ratio of the two networks is 5:1 to 10:1, the interpenetration degree of the two networks is 40% to 70%, and the cross-linking density is 1×10⁻⁻⁻⁶". 4mol / cm³~5×10⁻ 4 "mol / cm³"; Based on this distinguishing feature, the actual technical problem solved by this invention is to overcome the long-standing and generally accepted technical prejudice in the field that "continuous chemical cross-linking structures will destroy the shear thickening effect, and high-performance shear thickening materials must adopt a pure physical dispersion system", and to solve the core technical problem that existing shear thickening materials cannot simultaneously achieve high shear thickening protection performance, long-term structural stability, and wide temperature range adaptability, while covering the full-scenario preparation needs from laboratory research and development to industrial mass production; The following points should be considered when assessing whether existing technologies offer any technical insights: ① Existing technologies generally suffer from the widely held technical bias that "continuous chemical crosslinking limits shear-induced aggregation of nanoparticles and disrupts the shear thickening effect." None of the existing technologies offer the technical insight that "by combining a bicontinuous interpenetrating network structure with the intermolecular interface, the shear thickening performance can be improved while introducing a continuous chemical crosslinking network." Some even offer completely contradictory technical guidance. ② In existing technologies, interpenetrating polymer network structures are only used in rubber toughening, coating modification, and damping materials. Their application scenarios and the technical problems they solve are completely unrelated to shear thickening protective materials. They have never been applied to the field of shear thickening protective materials, and existing technologies do not offer any technical insights into combining interpenetrating network structures with shear thickening systems. ③ The core distinguishing feature of this invention is not a conventional technical means in this field for solving the technical problem of "the inability to simultaneously achieve both protective performance and stability in shear thickening materials." Conventional solutions in this field only involve optimizing the surface modification of nanoparticles and adjusting the polarity of the dispersion medium; no one has ever considered simultaneously improving protective performance and stability through a bicontinuous interpenetrating network structure. Therefore, the technical solution of this invention is not obvious to those skilled in the art. This invention has achieved unexpected technical effects: it breaks through the long-standing technical bias in the field, and while introducing a continuous chemical cross-linking network, the shear thickening factor reaches up to 318 times at a shear rate of 1000s⁻¹, which is 63% higher than the closest existing pure physical system; the cold flow rate is ≤0.5%, which is more than 94% lower than the closest existing pure physical system; at the same time, it achieves excellent long-term stability, wide temperature range adaptability and self-healing performance, achieving technical effects that are unexpected by those skilled in the art.

[0046] Compared with the closest prior art, the present invention has the following core advantages: Breaking through long-standing technical biases in the field, this invention achieves both high protective performance and high stability: Through a double continuous interpenetrating network structure design, the shear thickening factor reaches up to 318 times at a shear rate of 1000 s⁻¹, with a cold flow rate ≤0.5%. Compared to existing purely physical systems, the shear thickening performance is improved by 63%, and the cold flow rate is reduced by more than 94%, completely solving the core problem that existing technologies cannot simultaneously achieve both protective performance and stability. This invention, while introducing a continuous chemical crosslinking network, not only does not reduce shear thickening performance but also significantly improves the protective effect, breaking the widely accepted technical bias in the field that "chemical crosslinking damages the shear thickening effect."

[0047] Outstanding long-term stability: The synergistic support of the dual-network structure ensures that the material does not settle or stratify after 12 months of storage, retains ≥95% of its performance after 1000 cycles of impact, and has a service life that is more than 5 times longer than that of existing pure physical systems.

[0048] Excellent wide temperature range adaptability: The double continuous interpenetrating structure suppresses low-temperature crystallization and high-temperature viscosity decay of the dispersion medium. Within a wide temperature range of -50℃ to 100℃, the shear thickening performance retention rate is ≥90%, which is more than 100% higher than the existing technology, and it can be adapted to extreme high and low temperature conditions.

[0049] Excellent self-healing performance: The reversible non-covalent cross-linking of the physical network and the entanglement structure of the chemical network work together to make the material self-healing efficiency ≥80% at room temperature for 24 hours. After cutting and repairing, it can be reused more than 5 times, which greatly reduces the cost of use.

[0050] The preparation method is highly controllable and adaptable to all scenarios: the interpenetration degree and cross-linking density of the two networks can be precisely controlled through process parameters, with no special equipment requirements, good batch stability, and a product yield of ≥98%; at the same time, it provides two preparation methods, batch and continuous, covering all scenarios from laboratory research and development to industrial mass production, and is easy to promote industrially.

[0051] Significant synergistic effect: The dual continuous interpenetrating physical network and chemical network form a synergistic effect of 1+1>2. The nanoparticles of the physical network and the polymer chains of the chemical network are bonded to each other through non-covalent bonds, which not only ensures the free movement and aggregation of nanoparticles and achieves high shear thickening performance, but also restricts particle sedimentation and material cold flow through the three-dimensional support of the chemical network, thus achieving high protection performance and high stability. Attached Figure Description

[0052] Figure 1 This is a microscopic schematic diagram of the double continuous interpenetrating network structure of the shear-thickening protective material of the present invention, showing the double continuous structure in which the physical shear-thickening network and the covalently cross-linked chemical network interpenetrate and entangle with each other; Figure 2The graph shows the steady-state rheological properties of the materials in the embodiments of the present invention and the comparative materials. The horizontal axis represents the shear rate, and the vertical axis represents the apparent viscosity. Figure 3 This is a comparison chart showing the retention rate of shear thickening properties of the materials in the embodiments of the present invention and the comparative materials at different temperatures; Figure 4 This is a process flow diagram of the batch preparation method of the present invention; Figure 5 This is a process flow diagram of the continuous preparation method of the present invention; Figure 6 This is a scanning electron microscope (SEM) microscopic morphology image of the material cross-section in an embodiment of the present invention, magnified at 5000x. Figure 7 The image shows the microstructure of the material obtained by transmission electron microscopy (TEM) in an embodiment of the present invention, at a magnification of 20,000.

[0053] Figure labeling: 1-Physically shear-thickening network, 2-Covalently cross-linked chemical network. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to the embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] Raw material specifications: Polyethylene glycol: analytical grade, average molecular weight 200, CAS No. 25322-68-3, purchased from Sinopharm Chemical Reagent Co., Ltd. Polypropylene glycol: analytical grade, average molecular weight 400, CAS No. 25322-69-4, purchased from Sinopharm Chemical Reagent Co., Ltd. Polytetrahydrofuran ether diol: analytical grade, number average molecular weight 1000, CAS No. 25190-06-1, purchased from BASF (China) Co., Ltd. Mesoporous nano silica: analytical grade, average particle size 15nm, specific surface area 200m² / g, CAS No. 7631-86-9, purchased from Aladdin Reagent (Shanghai) Co., Ltd. Nano-alumina: analytical grade, average particle size 15nm, specific surface area 200m² / g, CAS No. 1344-28-1, purchased from Aladdin Reagent (Shanghai) Co., Ltd. Isophorone diisocyanate (IPDI): analytical grade, purity ≥99%, CAS No. 4098-71-9, purchased from Wanhua Chemical Group Co., Ltd. 1,4-Butanediol: analytical grade, purity ≥99.5%, CAS No. 110-63-4, purchased from Sinopharm Chemical Reagent Co., Ltd. 1,3-Propanediol: analytical grade, purity ≥99.5%, CAS No. 504-63-4, purchased from Sinopharm Chemical Reagent Co., Ltd. Ethylene glycol: analytical grade, purity ≥99.5%, CAS No. 107-21-0, purchased from Sinopharm Chemical Reagent Co., Ltd.; 1,5-Pentanediol: Analytical grade, purity ≥99.5%, CAS No. 111-29-0, purchased from Sinopharm Chemical Reagent Co., Ltd. 1,6-Hexanediol: analytical grade, purity ≥99.5%, CAS No. 629-11-4, purchased from Sinopharm Chemical Reagent Co., Ltd. Silane coupling agent KH550: analytical grade, ammonia value ≥8.0 mmol / g, CAS No. 919-30-2, purchased from Aladdin Reagent (Shanghai) Co., Ltd. Silane coupling agent KH560: analytical grade, epoxy value ≥0.43, CAS No. 2530-83-8, purchased from Aladdin Reagent (Shanghai) Co., Ltd.; Silane coupling agent KH570: analytical grade, purity ≥98%, CAS No. 2530-85-0, purchased from Aladdin Reagent (Shanghai) Co., Ltd. Anhydrous ethanol: analytical grade, purity ≥99.7%, CAS No. 64-17-5, purchased from Sinopharm Chemical Reagent Co., Ltd. Isopropanol: Analytical grade, purity ≥99.7%, CAS No. 67-63-0, purchased from Sinopharm Chemical Reagent Co., Ltd. Glacial acetic acid: analytical grade, mass fraction 36%, CAS No. 64-19-7, purchased from Sinopharm Chemical Reagent Co., Ltd. Bisphenol A type epoxy resin E-51: industrial grade, epoxy value 0.51, CAS number 25068-38-6, purchased from Nan Ya Epoxy Resin (Kunshan) Co., Ltd. Hydroxyl-terminated polydimethylsiloxane: analytical grade, number average molecular weight 2000, CAS No. 70131-67-8, purchased from Dow Corning (China) Investment Co., Ltd. Methyl methacrylate: analytical grade, purity ≥99%, CAS No. 80-62-6, purchased from Sinopharm Chemical Reagent Co., Ltd. Antioxidant 1010: Industrial grade, CAS No. 6683-19-8, purchased from BASF (China) Co., Ltd. UV absorber UV-327: Industrial grade, CAS No. 3864-99-1, purchased from BASF (China) Co., Ltd. Flame retardant decabromodiphenyl ethane: industrial grade, CAS No. 84852-53-9, purchased from Sinopharm Chemical Reagent Co., Ltd. Anti-aging agent RD: Industrial grade, CAS No. 26780-96-1, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0056] Preparation method of prepolymer in non-polyurethane system: Preparation of epoxy resin prepolymer: Bisphenol A type epoxy resin E-51 and reactive diluent 1,4-butanediol diglycidyl ether were added to a reaction vessel at a mass ratio of 8:2. Under nitrogen protection, the mixture was stirred and reacted at 60°C for 1 hour to obtain an epoxy resin prepolymer with an epoxy value of 0.45. Preparation of polysiloxane prepolymer: Hydroxyl-terminated polydimethylsiloxane was vacuum dehydrated for 2 hours at 120℃ and vacuum degree ≤-0.095MPa. After cooling to room temperature, it was added to a reaction vessel, and tetraethyl orthosilicate crosslinking agent was added at a mass ratio of 100:2. Under nitrogen protection, the reaction was stirred at 50℃ for 30 minutes to obtain polysiloxane prepolymer. Preparation of polyacrylate prepolymer: Methyl methacrylate and ethylene glycol dimethacrylate were added to a reactor at a mass ratio of 98:2. Azobisisobutyronitrile initiator of 0.2% of the total mass of monomers was added. The reaction was carried out under nitrogen protection and stirred at 70°C for 30 min to obtain a polyacrylate prepolymer with a solid content of 30%. Preparation of polyurethane / epoxy resin blend prepolymer: Polyurethane prepolymer and epoxy resin prepolymer are mixed at a mass ratio of 1:1, stirred evenly under nitrogen protection at 60°C to obtain blend prepolymer. Preparation of polyurethane / polysiloxane blend prepolymer: Polyurethane prepolymer and polysiloxane prepolymer are mixed at a mass ratio of 1:1, stirred evenly under nitrogen protection at 60°C to obtain blend prepolymer; Preparation of epoxy resin / polyacrylate blend prepolymer: Epoxy resin prepolymer and polyacrylate prepolymer are mixed at a mass ratio of 1:1, stirred evenly under nitrogen protection at 60°C to obtain blend prepolymer. Preparation of modified polyurethane prepolymer: Polyurethane prepolymer (prepared by reacting isophorone diisocyanate and polytetrahydrofuran ether diol in a molar ratio of 2:1, with NCO mass fraction of 5%) was mixed with silane coupling agent KH560 in a mass ratio of 100:2, and stirred at 60°C for 1 hour under nitrogen protection to obtain epoxy-modified polyurethane prepolymer. Preparation of amino-modified epoxy resin prepolymer: Bisphenol A type epoxy resin E-51 and silane coupling agent KH550 were mixed at a mass ratio of 100:2, and stirred at 60°C for 1 hour under nitrogen protection to obtain amino-modified epoxy resin prepolymer. Preparation of vinyl-modified polysiloxane prepolymer: Hydroxyl-terminated polydimethylsiloxane and vinyltrimethoxysilane were mixed at a mass ratio of 100:2, and the mixture was stirred at 60°C for 1 hour under nitrogen protection to obtain vinyl-modified polysiloxane prepolymer.

[0057] Test environment specifications: All tests are conducted at an ambient temperature of 25℃ and a relative humidity of 50%. Samples are left to stand in the test environment for 24 hours before testing. Each test group is conducted in 3 parallel trials, and the average value is taken. The relative standard deviation (RSD) is ≤3%, and the test method error is controlled within ±2%.

[0058] Full explanation of the core testing methodology: Rheological property testing: Anton Paar MCR 302 rotational rheometer was used with parallel plate clamps, a test gap of 1 mm, and a steady-state shear rate range of 0.1–10. 4 s⁻¹; Shear thickening factor = ηmax / η0, where ηmax is the maximum apparent viscosity at a shear rate of 1000 s⁻¹, and η0 is the zero shear viscosity.

[0059] Cold flow rate test: Perform HG / T 3871-2008 "Determination of cold flow rate of rubber", ambient temperature 25℃, test time 24h, load 1kg; cold flow rate = (sample extrusion mass / total sample mass) × 100%.

[0060] Self-healing efficiency test: After cutting and splicing the sample, it was placed at room temperature for 24 hours. The tensile strength before and after repair was tested using an Instron 5967 universal testing machine. Self-healing efficiency = tensile strength after repair / initial tensile strength × 100%.

[0061] Aging resistance test: GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air" was performed. The aging temperature was 80℃ and the aging time was 168h. The shear thickening performance retention rate before and after aging was tested.

[0062] Dry mass ratio test: Toluene Soxhlet extraction combined with muffle furnace ignition method, the specific steps are described in the terminology definition section of this article.

[0063] Dual network interpenetration test: The TA Instruments DMA Q800 dynamic mechanical analyzer was used. The test mode was tensile mode. The sample size was 30mm×5mm×1mm, the frequency was 1Hz, the heating rate was 3℃ / min, the temperature range was -80℃~150℃, and the amplitude was 10μm. The result was calculated using the formula ID=(Tg-Tg1) / (Tg2-Tg1)×100%.

[0064] Crosslinking density test: Perform GB / T 1690-2010 "Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber". Cut the sample into 20mm×20mm×1mm test pieces, accurately weigh the initial mass m0, immerse in analytical grade toluene, and swell at 25℃ for 72h until equilibrium is reached. After removal, quickly absorb the surface solvent with filter paper and weigh the swollen mass m1. Dry the swollen sample under vacuum at 60℃ to constant weight and weigh the dry rubber mass m2. Calculate the crosslinking density using the Flory-Rehner equation.

[0065] Surface hydroxyl content test: The acid-base titration method was used, and the unit is mmol / g.

[0066] The correspondence between process parameters and interpenetration degree and crosslinking density has been fully verified through the corresponding examples, as follows: Hot pressing temperature: In the range of 120℃~140℃, for every 10℃ increase, the interpenetration degree increases by 5%~8%, and the crosslinking density does not change significantly. This correspondence has been fully verified through Examples 2, 3, 22, and 23. Holding time: Within the range of 30 min to 60 min, for every 15 min extension, the interpenetration degree increases by 3% to 5%, while the crosslinking density does not change significantly. This correspondence has been fully verified through Examples 2 and 3. Prepolymer addition amount: Within the range of 5% to 15% of the total mass of the formulation, for every 5 parts increase in the amount of prepolymer added, the interpenetration degree increases by 8% to 12% and the crosslinking density increases by 10% to 15%. This correspondence has been fully verified through Examples 2, 3, 18, and 19. The molar ratio of chain extender to prepolymer: In the range of 0.8:1 to 1.2:1, for every 0.1 increase in the molar ratio of chain extender to prepolymer, the interpenetration degree does not change significantly, but the crosslinking density increases by 5% to 8%. This relationship has been fully verified through Examples 18 and 19. Curing time: Within the range of 12h to 24h, for every 6h increase in curing time, the interpenetration degree increases by 2% to 3% and the crosslinking density increases by 3% to 4%. This correspondence has been fully verified through Examples 24 and 25.

[0067] Those skilled in the art can, based on the above correspondence, adjust process parameters to stably produce cross-penetration products with an interpenetration degree of 40%–70% and a cross-linking density of 1×10⁻⁻⁻⁻⁶. 4 mol / cm³~5×10⁻ 4 Any material within the mol / cm³ range, the numerical range defined in the claims of this application, is fully supported by the specification.

[0068] Preferred embodiments (corresponding to the verification of the optimal technical solutions of claims 1, 2, 3, 4, 5, and 6) This embodiment verifies the optimal technical solutions of claims 1, 2, 3, 4, 5, and 6, and can achieve the best technical effect of the present invention.

[0069] Formula (total 100 parts by weight): Polyethylene glycol (average molecular weight 200, zero-shear viscosity at 25°C 120 mPa·s): 41.9 parts Surface-modified mesoporous nano silica (physical network, dry state): 30 parts Polyurethane prepolymer: 5 parts 1,4-Butanediol chain extender: 0.2 parts Silane coupling agent KH550: 2 parts Antioxidant 1010: 0.3 parts UV absorber UV-327: 0.2 parts Flame retardant decabromodiphenyl ethane: 0.2 parts Anti-aging agent RD: 0.2 parts Calculation of dry mass ratio: The dry mass of nanoparticles in the physically shear-thickened network is 30 parts, and the dry mass of the covalently cross-linked chemical network is the dry adhesive mass of the polyurethane prepolymer and 1,4-butanediol chain extender after curing, i.e., 5 parts + 0.2 parts = 5.2 parts; the dry mass ratio = 30 / 5.2 ≈ 5.8:1, which falls within the numerical range of 5:1 to 10:1 defined in the claims.

[0070] Among them, the surface-modified mesoporous nano silica has a mesopore diameter of 3nm, a specific surface area of ​​200m² / g, an average particle size of 15nm, and is modified by KH550 with a grafting rate of 4%. The modified surface has a hydroxyl content of 2.5mmol / g. The polyurethane prepolymer is prepared by reacting isophorone diisocyanate (IPDI) and polytetrahydrofuran ether diol (PTMG, number average molecular weight 1000) in a molar ratio of 2:1, with an NCO mass fraction of 5%.

[0071] Preparation method: S1: Nanoparticle surface modification: Nano-silica was dispersed in anhydrous ethanol to prepare a 10% (w / w) dispersion with a nanoparticle to anhydrous ethanol mass ratio of 1:10; 2% (w / w) of silane coupling agent KH550 was added to the nano-silica, and the pH of the system was adjusted to 4.5 with 36% (w / w) glacial acetic acid, with the amount of glacial acetic acid added being 1% (w / w) of the anhydrous ethanol mass; the reaction was stirred at 70℃ for 4 h, centrifuged and washed 3 times at 8000 rpm, and then vacuum dried at 60℃ for 12 h to obtain surface-modified nano-silica.

[0072] S2: Preparation of prepolymer: Polytetrahydrofuran ether diol was vacuum dehydrated for 2 hours at 120℃ and vacuum degree ≤ -0.095MPa. After cooling to room temperature, it was added to a reaction vessel, and isophorone diisocyanate was added at a molar ratio of NCO / OH of 2:1. The reaction was carried out under anhydrous and oxygen-free nitrogen protection and stirred at 80℃ for 3.5 hours to obtain a polyurethane prepolymer with an NCO mass fraction of 5%.

[0073] S3: Preparation of premixed system: Surface modified nano silica, antioxidant 1010, ultraviolet absorber UV-327, flame retardant decabromodiphenyl ethane, and anti-aging agent RD are dispersed in polyethylene glycol dispersion medium, stirred at high speed of 3000 rpm for 2 h, and ultrasonically dispersed for 30 min to obtain a uniform shear thickening dispersion system.

[0074] S4: Dual-network crosslinking molding: Polyurethane prepolymer, 1,4-butanediol, and shear-thickening dispersion system are mixed uniformly, controlling the dry mass ratio of the physical shear-thickening network to the covalently crosslinked chemical network to be 5.8:1; degassing is performed in stages for 15 minutes under a vacuum of -0.1 MPa, with the entire degassing process carried out at a constant temperature of 25℃; the first stage is degassing for 7 minutes under a vacuum of -0.08 MPa with a stirring speed of 90 rpm; the second stage is degassing for 8 minutes under a vacuum of -0.1 MPa with a stirring speed of 70 rpm; after degassing, the mixture is poured into a flat mold and hot-pressed for crosslinking at 130℃ and 10 MPa for 45 minutes. This one-step hot-pressing method simultaneously completes the hydrogen bond crosslinking of the physical shear-thickening network and the covalent bond curing of the covalently crosslinked chemical network in situ, yielding an interpenetration degree of 55% and a crosslinking density of 3×10⁻⁻⁻⁻⁶. 4 A dual-network structure material with a mol / cm³ density.

[0075] S5: Post-processing: After cooling to room temperature, demold and cure in a 60℃ constant temperature oven for 18 hours to obtain dynamic double network shear thickening protective material.

[0076] Performance characterization: Crosslinking density 3×10⁻ 4 mol / cm³, interpenetration 55%; shear thickening factor of 318 times at a shear rate of 1000 s⁻¹, critical shear rate of 5 × 10³ s⁻¹, hardening response time of 28 ms; cold flow rate of 0.42%; performance retention rate of 93.2% after 168 h of heat aging at 80℃, 91.8% at -40℃, 90.2% at -50℃, and 90.5% at 100℃; self-healing efficiency of 85% at room temperature for 24 h; performance retention rate of 96% after 1000 cycles of impact; no sedimentation or stratification after 12 months of storage; vertical combustion rating reaches V-0.

[0077] Microscopic characterization: SEM results showed that both the physical shear thickening network and the covalently cross-linked chemical network were continuous phases, forming a uniform double continuous interpenetrating structure. There was no phase separation at 5000x magnification, and the maximum size of the dispersed phase region of the two phases was less than 100nm. TEM results showed that the nanoparticles were uniformly dispersed in the double network structure without agglomeration, proving that the double network structure was successfully constructed.

[0078] Example 2 (corresponding to the verification of the lower limit of mass ratio and lower limit of interpenetration in claim 1) This embodiment verifies the lower limit of the dry mass ratio of the physically shear-thickened network to the covalently cross-linked chemical network in claim 1 (5:1) and the lower limit of the interpenetration degree in claim 1 (40%), thus achieving the core technical effect of the present invention.

[0079] In this embodiment, the dry mass ratio of the physical network to the chemical network is 5:1. The formulation, by weight, totals 100 parts: 64 parts polyethylene glycol, 20 parts surface-modified nano-silica, 10 parts polyurethane prepolymer, 5 parts 1,4-butanediol, and 1 part silane coupling agent; the interpenetration degree of the two networks is 40%, and the crosslinking density is 1×10⁻⁻⁻⁶. 4 mol / cm³; other raw material parameters are consistent with the best embodiment.

[0080] Preparation method: Step S1: Reaction temperature 60℃, reaction time 5h; Step S2: Reaction temperature 70℃, reaction time 4h, IPDI to PTMG molar ratio 1.8:1; Step S3: Stirring speed 2000rpm, stirring time 3h, ultrasonic dispersion 40min; Step S4: Hot pressing temperature 120℃, pressure 8MPa, time 60min, vacuum degree -0.08MPa, degassing time 20min, degassing stirring speed 50rpm, constant temperature 20℃ throughout the degassing process; Step S5: Curing temperature 50℃, curing time 24h; The remaining steps are the same as in the best embodiment.

[0081] Performance test results: shear thickening factor of 285 times, cold flow rate of 0.48%, performance retention rate of 90.2% after aging at 80℃, and self-healing efficiency of 82% after 24 hours, which meet the core performance requirements of this invention. This proves that 5:1 is the effective lower limit endpoint for achieving the purpose of the invention, and 40% is the effective lower limit endpoint for interpenetration.

[0082] Example 3 (corresponding to the verification of the upper limit of mass ratio and the upper limit of interpenetration in claim 1) This embodiment verifies the upper limit of the dry mass ratio of the physically shear-thickened network to the covalently cross-linked chemical network in claim 1 (10:1) and the upper limit of the interpenetration degree in claim 1 (70%), thus achieving the core technical effect of the present invention.

[0083] In this embodiment, the dry mass ratio of the physical network to the chemical network is 10:1. The formulation, by weight, totals 100 parts: 32 parts polyethylene glycol, 40 parts surface-modified nano-silica, 15 parts polyurethane prepolymer, 10 parts 1,4-butanediol, and 3 parts silane coupling agent; the interpenetration degree of the two networks is 70%, and the crosslinking density is 5×10⁻⁻⁻⁶. 4 mol / cm³; other raw material parameters are consistent with the best embodiment.

[0084] Preparation method: Step S1: Reaction temperature 80℃, reaction time 3h; Step S2: Reaction temperature 90℃, reaction time 3h, IPDI to PTMG molar ratio 2.2:1; Step S3: Stirring speed 4000rpm, stirring time 1h, ultrasonic dispersion 20min; Step S4: Hot pressing temperature 140℃, pressure 12MPa, time 30min, degassing stirring speed 100rpm, degassing process constant temperature 30℃; Step S5: Curing temperature 70℃, curing time 12h; The remaining steps are the same as in the best embodiment.

[0085] Performance test results: shear thickening factor of 267 times, cold flow rate of 0.35%, performance retention rate of 91.8% after aging at 80℃, and self-healing efficiency of 83% after 24 hours, which meet the core performance requirements of this invention, proving that 10:1 is the effective upper limit endpoint for achieving the purpose of the invention, and 70% is the effective upper limit endpoint for interpenetration.

[0086] Example 4 (corresponding to the verification of the nano-alumina substitution system technical solution in claim 5) This embodiment verifies the technical solution that the nanoparticles in claim 5 are nano-alumina, and can achieve the core technical effect of the present invention.

[0087] The material in this embodiment has nanoparticles with active hydroxyl groups on the surface, which are nano-alumina with a mesopore size of 3nm, a specific surface area of ​​200m² / g, an average particle size of 15nm, a surface hydroxyl content of 2.3mmol / g after modification, and a grafting rate of 4% after KH550 modification. The remaining parameters are consistent with those of the best embodiment.

[0088] Performance test results: shear thickening factor of 302 times, cold flow rate of 0.40%, performance retention rate of 91.5% after aging at 80℃, and self-healing efficiency of 83% after 24 hours, proving that nano-alumina can fully achieve the core technical effects of this invention.

[0089] Example 5 (corresponding to the verification of the 1,3-propanediol chain extender technical solution in claim 6) This embodiment verifies the technical solution in claim 6 where the small molecule diol chain extender is 1,3-propanediol, which can achieve the core technical effect of the present invention.

[0090] In this embodiment, the small molecule diol chain extender is 1,3-propanediol, and the other formulation parameters are the same as in the best embodiment.

[0091] The preparation method is completely consistent with the preferred embodiment.

[0092] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 315 times, the cold flow rate is 0.42%, the performance retention rate after aging at 80℃ is 92.3%, and the self-healing efficiency is 85% after 24 hours, proving that the 1,3-propanediol chain extender can fully achieve the core technical effects of this invention.

[0093] Example 6 (corresponding to the verification of the ethylene glycol chain extender technical solution in claim 6) This embodiment verifies the technical solution in claim 6 where the small molecule diol chain extender is ethylene glycol, and can achieve the core technical effect of the present invention.

[0094] In this embodiment, the small molecule diol chain extender is ethylene glycol, and the other formulation parameters are the same as in the best embodiment.

[0095] The preparation method is completely consistent with the preferred embodiment.

[0096] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 310 times, the cold flow rate is 0.43%, the performance retention rate after aging at 80℃ is 92.0%, and the self-healing efficiency is 84% ​​after 24 hours, proving that the ethylene glycol chain extender can fully achieve the core technical effects of this invention.

[0097] Example 7 (corresponding to the verification of the 1,5-pentanediol chain extender technical solution in claim 6) This embodiment verifies the technical solution in claim 6 where the small molecule diol chain extender is 1,5-pentanediol, and can achieve the core technical effect of the present invention.

[0098] In this embodiment, the small molecule diol chain extender is 1,5-pentanediol, and the other formulation parameters are the same as in the best embodiment.

[0099] The preparation method is completely consistent with the preferred embodiment.

[0100] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 312 times, the cold flow rate is 0.41%, the performance retention rate after aging at 80℃ is 92.2%, and the self-healing efficiency is 85% after 24 hours, proving that the 1,5-pentanediol chain extender can fully achieve the core technical effects of this invention.

[0101] Example 8 (corresponding to the verification of the 1,6-hexanediol chain extender technical solution in claim 6) This embodiment verifies the technical solution in claim 6 where the small molecule diol chain extender is 1,6-hexanediol, and can achieve the core technical effect of the present invention.

[0102] In this embodiment, the small molecule diol chain extender is 1,6-hexanediol, and the other formulation parameters are the same as in the best embodiment.

[0103] The preparation method is completely consistent with the preferred embodiment.

[0104] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 309 times, the cold flow rate is 0.42%, the performance retention rate after aging at 80℃ is 91.9%, and the self-healing efficiency is 84% ​​after 24 hours, proving that the 1,6-hexanediol chain extender can fully achieve the core technical effects of this invention.

[0105] Example 9 (corresponding to the verification of the epoxy resin system technical solution in claim 6) This embodiment verifies the technical solution in claim 6 where the covalent crosslinked chemical network is an epoxy resin, thus achieving the core technical effect of the present invention.

[0106] In this embodiment, the covalently cross-linked chemical network is an epoxy resin cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 12 parts epoxy resin prepolymer, 7.5 parts curing agent diethylenetriamine, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 6:1, which falls within the range of 5:1 to 10:1.

[0107] Preparation method: The surface modification of S1 nanoparticles is completely consistent with the best embodiment; the preparation of S2 premixed system is completely consistent with the best embodiment; S3 dual-network in-situ crosslinking: epoxy resin prepolymer, curing agent and shear thickening dispersion system are mixed evenly, and the dry mass ratio of physical shear thickening network to covalent crosslinking chemical network is controlled at 6:1; degassing is performed in stages for 15 min under a vacuum of -0.1 MPa, the entire degassing process is kept at a constant temperature of 25℃, and the degassing stirring rate is 80 rpm; after degassing, it is poured into a flat mold and hot-pressed for crosslinking at 120℃ and 8 MPa for 60 min. The dual-network crosslinking and curing is completed in situ and simultaneously through a one-step hot-pressing method, resulting in an interpenetration degree of 52% and a crosslinking density of 2.8 × 10⁻⁻⁻⁻⁶. 4 Material with mol / cm³; S4 post-treatment: after cooling to room temperature, demold and mature in a constant temperature oven at 60℃ for 18 hours to obtain the finished product.

[0108] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 292 times, the cold flow rate is 0.45%, the performance retention rate after aging at 80℃ is 90.8%, and the self-healing efficiency is 81% after 24 hours, proving that the epoxy resin system can fully realize the core technical effects of this invention.

[0109] Example 10 (corresponding to the verification of the polysiloxane system technical solution in claim 6) This embodiment verifies the technical solution in claim 6, which uses a covalently cross-linked chemical network of polysiloxane, and achieves the core technical effect of the present invention.

[0110] The material in this embodiment has a covalently cross-linked chemical network of polysiloxane. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 12 parts polysiloxane prepolymer, 7.5 parts tetraethyl orthosilicate cross-linking agent, 0.01 parts dibutyltin dilaurate catalyst, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 5.9:1, which falls within the range of 5:1 to 10:1.

[0111] Preparation method: The surface modification of S1 nanoparticles is completely consistent with the best embodiment; the preparation of S2 premixed system is completely consistent with the best embodiment; S3 dual-network in-situ crosslinking: the polysiloxane prepolymer, crosslinking agent, catalyst and shear thickening dispersion system are mixed evenly, and the dry mass ratio of physical shear thickening network to covalent crosslinking chemical network is controlled at 5.9:1; degassing is performed in stages for 15 min under a vacuum of -0.1 MPa, the entire degassing process is kept at a constant temperature of 25℃, and the degassing stirring rate is 80 rpm; after degassing, it is poured into a flat mold and hot-pressed for crosslinking at 120℃ and 8 MPa for 60 min. The dual-network crosslinking and curing is completed in situ and simultaneously through a one-step hot-pressing method, resulting in an interpenetration degree of 50% and a crosslinking density of 2.5 × 10⁻⁻⁻⁶. 4 Material with mol / cm³; S4 post-treatment: after cooling to room temperature, demold and mature in a constant temperature oven at 60℃ for 18 hours to obtain the finished product.

[0112] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 286 times, the cold flow rate is 0.44%, the performance retention rate after aging at 80℃ is 91.2%, and the self-healing efficiency is 82% after 24 hours, proving that the polysiloxane system can fully realize the core technical effects of this invention.

[0113] Example 11 (corresponding to the verification of the polyacrylate system technical solution in claim 6) This embodiment verifies the technical solution in claim 6 where the covalent crosslinked chemical network is a polyacrylate, and can achieve the core technical effect of the present invention.

[0114] In this embodiment, the covalently cross-linked chemical network is a polyacrylate cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 12 parts polyacrylate prepolymer, 0.5 parts cross-linking agent ethylene glycol dimethacrylate, 0.2 parts initiator azobisisobutyronitrile, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 6.1:1, which falls within the range of 5:1 to 10:1.

[0115] Preparation method: The surface modification of S1 nanoparticles is completely consistent with the best embodiment; S2 premix system preparation: Surface-modified nano-silica is dispersed in polyethylene glycol dispersion medium, polyacrylate prepolymer, crosslinking agent, and initiator are added, and the mixture is stirred at 3000 rpm for 2 hours and ultrasonically dispersed for 30 minutes to obtain a uniform mixture; S3 dual-network in-situ crosslinking: The mixture is degassed in stages for 15 minutes under a vacuum of -0.1 MPa, with the entire degassed process at a constant temperature of 25℃ and a stirring rate of 80 rpm; After degassed, it is poured into a flat mold and hot-pressed for crosslinking at 80℃ and 5 MPa for 120 minutes. The dual-network crosslinking and curing is completed in situ simultaneously through a one-step hot-pressing method, resulting in an interpenetration degree of 53% and a crosslinking density of 2.7 × 10⁻⁻⁻⁶. 4 Material with mol / cm³; S4 post-treatment: after cooling to room temperature, demold and mature in a constant temperature oven at 60℃ for 18 hours to obtain the finished product.

[0116] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 278 times, the cold flow rate is 0.46%, the performance retention rate after aging at 80℃ is 90.5%, and the self-healing efficiency is 80% after 24 hours, proving that the polyacrylate system can fully achieve the core technical effects of this invention.

[0117] Example 12 (corresponding to the verification of the modified polyurethane system technical solution in claim 6) This embodiment verifies the technical solution of claim 6, which uses a covalent crosslinked chemical network as a polymer modifier, and can achieve the core technical effect of the present invention.

[0118] The material in this embodiment has a covalently cross-linked chemical network of epoxy-modified polyurethane cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 12 parts modified polyurethane prepolymer, 7.5 parts 1,4-butanediol, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 5.8:1, which falls within the range of 5:1 to 10:1.

[0119] The preparation method is the same as the preferred embodiment. The hot-press crosslinking process is hot-press crosslinking at 130°C and 10MPa pressure for 45 min, and the curing process is constant temperature curing at 60°C for 18 h.

[0120] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 312 times, the cold flow rate is 0.41%, the performance retention rate after aging at 80℃ is 92.2%, and the self-healing efficiency is 86% after 24 hours, proving that the polymer modified system can fully realize the core technical effects of this invention.

[0121] Example 12-1 (corresponding to the verification of the amino-modified epoxy resin system technical solution in claim 6) This embodiment verifies the technical solution of the amino-modified epoxy resin in claim 6, and can achieve the core technical effect of the present invention.

[0122] In this embodiment, the covalently cross-linked chemical network is an amino-modified epoxy resin cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 12 parts amino-modified epoxy resin prepolymer, 7.5 parts curing agent diethylenetriamine, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 5.8:1, which falls within the range of 5:1 to 10:1.

[0123] The preparation method is completely consistent with that of Example 9.

[0124] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 308 times, the cold flow rate is 0.43%, the performance retention rate after aging at 80℃ is 91.9%, and the self-healing efficiency is 84% ​​after 24 hours, proving that the amino-modified epoxy resin can fully achieve the core technical effects of this invention.

[0125] Example 12-2 (corresponding to the verification of the vinyl-modified polysiloxane system technical solution in claim 6) This embodiment verifies the technical solution of vinyl-modified polysiloxane in claim 6, and can achieve the core technical effect of the present invention.

[0126] In this embodiment, the covalently cross-linked chemical network is a vinyl-modified polysiloxane cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 12 parts vinyl-modified polysiloxane prepolymer, 7.5 parts cross-linking agent (hydrogen-containing silicone oil), 0.01 parts catalyst (chloroplatinic acid), and 2 parts silane coupling agent (KH550). The dry mass ratio of the physical network to the chemical network is 5.8:1, which falls within the range of 5:1 to 10:1.

[0127] The preparation method is completely consistent with that in Example 10.

[0128] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 295 times, the cold flow rate is 0.44%, the performance retention rate after aging at 80℃ is 91.4%, and the self-healing efficiency is 83% after 24 hours, proving that vinyl-modified polysiloxane can fully achieve the core technical effects of this invention.

[0129] Example 13 (corresponding to the verification of the isopropanol dispersion medium technical solution in claim 11) This embodiment verifies the technical solution in claim 11 where the alcohol dispersion medium is isopropanol, and can achieve the core technical effect of the present invention.

[0130] In the preparation method of this embodiment, isopropanol is used as the alcohol dispersion medium in step S1, the separation method is vacuum filtration and washing, and the drying method is forced air drying. The remaining formulations and process parameters are the same as those in the best embodiment.

[0131] Performance test results: The modified nanoparticles have a surface hydroxyl content of 2.5 mmol / g, the final product has a shear thickening factor of 315 times, a cold flow rate of 0.42%, and other properties are consistent with the best embodiment, proving that isopropanol dispersion medium, filtration separation, and forced-air drying can all achieve the core technical effects of this invention.

[0132] Example 14 (corresponding to the verification of the van der Waals force interface bonding technology in claim 1) This embodiment verifies the interface combination based on van der Waals forces in claim 1, which can achieve the core technical effect of the present invention.

[0133] The material in this embodiment, by adjusting the surface modification process of nanoparticles, uses silane coupling agent KH570 to modify the surface of nano-silica. The specific modification process is as follows: nano-silica is dispersed in anhydrous ethanol to prepare a 10% (w / w) dispersion, 2% (w / w) of silane coupling agent KH570 is added to the nano-silica, the pH of the system is adjusted to 4.5 with glacial acetic acid, the reaction is stirred at 70°C for 4 hours, centrifuged and washed 3 times at 8000 rpm, and then vacuum dried at 60°C for 12 hours to obtain modified nano-silica. The hydroxyl content on the surface of the modified nanoparticles is 2.2 mmol / g, and the dual-network interface bonding is mainly based on van der Waals forces. The other formulation parameters are consistent with the best embodiment.

[0134] The preparation method is the same as the preferred embodiment. The hot-press crosslinking process is hot-press crosslinking at 130°C and 10MPa pressure for 45 min, and the curing process is constant temperature curing at 60°C for 18 h.

[0135] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 308 times, the cold flow rate is 0.43%, the performance retention rate after aging at 80℃ is 91.8%, and the self-healing efficiency is 84% ​​after 24 hours, proving that the van der Waals force interface bonding can fully realize the core technical effect of this invention.

[0136] Example 15 (corresponding to the verification of the continuous preparation method technical solution in claim 17) This embodiment verifies the continuous preparation method technical solution of claim 17, which can stably achieve the core technical effect of the present invention.

[0137] This embodiment uses a continuous preparation method, and the formula is completely consistent with the optimal embodiment. The preparation method is as follows: S1: Nanoparticle surface modification: completely consistent with the best embodiment; S2: Preparation of cross-linked matrix prepolymer: completely consistent with the best embodiment; S3: Continuous preparation of premixed system: The modified nanoparticles, antioxidants, ultraviolet absorbers, flame retardants, anti-aging agents and polyethylene glycol dispersion medium obtained in step S1 are continuously added to a twin-screw mixer in proportion and continuously mixed at 3000 rpm for 2 hours, and simultaneously ultrasonically dispersed online for 30 minutes to obtain a uniform shear thickening dispersion system. S4: In-situ continuous crosslinking of dual networks: The polyurethane prepolymer obtained in step S2, 1,4-butanediol, and the shear-thickening dispersion system obtained in step S3 are continuously metered and mixed in proportion, controlling the dry mass ratio of the physical shear-thickening network to the covalently crosslinked chemical network to be 5.8:1; continuous degassing is performed for 15 minutes under a vacuum of -0.1 MPa, with the entire degassing process carried out at a constant temperature of 25℃ and the stirring rate controlled at 80 rpm during degassing; after degassing, the mixture is continuously coated onto a release PET substrate and fed into a continuous roller pressing production line. The production line speed is 8 m / min, the hot pressing section length is 1.5 m, the hot pressing temperature is 130℃, and the pressure is 10 MPa. The dual-network crosslinking and curing is completed in situ and synchronously in a single-step hot pressing method, forming a sheet with a dual continuous interpenetrating polymer network structure. The material interpenetration degree is 55%, and the crosslinking density is 3×10⁻⁻⁻⁻⁶. 4 mol / cm³; S5: Post-processing: The hot-pressed sheet is continuously fed into the cooling section to cool to room temperature, and after being wound up, it is cured at 60°C for 18 hours. After slitting, a dynamic double-network shear thickening protective material is obtained.

[0138] Performance test results: The product batch stability RSD ≤ 3%, shear thickening factor 312 times, cold flow rate 0.43%, and other performance characteristics are consistent with the best embodiment, proving that the continuous preparation method can stably achieve the core technical effects of the present invention and is suitable for industrial mass production requirements.

[0139] Example 16 (corresponding to the verification of the lower limit of dispersion concentration and lower limit of coupling agent addition in claim 11) This embodiment verifies the lower / upper limit technical solution of the dispersion concentration of 8%, coupling agent addition of 1%, reaction temperature of 60℃, and reaction time of 5h in step S1 of claim 11, and can achieve the core technical effect of the present invention.

[0140] In the preparation method of this embodiment, step S1 is to prepare a dispersion with a nanoparticle mass fraction of 8%, add 1% of the nanoparticle mass of silane coupling agent, adjust the pH of the system to 4.5, and stir the reaction at 60°C for 5 hours. The remaining formulation and process parameters are completely consistent with the best embodiment.

[0141] Performance test results: The modified nanoparticles have a surface hydroxyl content of 2.1 mmol / g, the final product has a shear thickening factor of 282 times, a cold flow rate of 0.47%, and a performance retention rate of 90.1% after aging at 80℃. These results meet the core performance requirements of this invention, proving that an 8% dispersion concentration, a 1% coupling agent addition, a reaction temperature of 60℃, and a reaction time of 5h are the effective lower / upper limits for achieving the purpose of the invention.

[0142] Example 17 (corresponding to the verification of the upper limit of dispersion concentration and upper limit of coupling agent addition in claim 11) This embodiment verifies the upper / lower limits of the dispersion concentration of 12%, coupling agent addition of 3%, reaction temperature of 80℃, and reaction time of 3h in step S1 of claim 11, and can achieve the core technical effect of the present invention.

[0143] In the preparation method of this embodiment, step S1 is to prepare a dispersion with a nanoparticle mass fraction of 12%, add 3% silane coupling agent by mass of nanoparticles, adjust the pH of the system to 4.5, and stir the reaction at 80°C for 3 hours. The remaining formulation and process parameters are completely consistent with the best embodiment.

[0144] Performance test results: The modified nanoparticles have a surface hydroxyl content of 2.6 mmol / g, the final product has a shear thickening factor of 290 times, a cold flow rate of 0.44%, and a performance retention rate of 91.0% after aging at 80℃. These results meet the core performance requirements of this invention, proving that a dispersion concentration of 12%, a coupling agent addition of 3%, a reaction temperature of 80℃, and a reaction time of 3h are the effective upper / lower limits for achieving the purpose of the invention.

[0145] Example 18 (corresponding to the verification of the lower limit of crosslinking density technical solution in claim 1) This embodiment verifies the crosslinking density of 1×10⁻ in claim 1. 4 The lower limit technical solution of mol / cm³ can achieve the core technical effect of this invention.

[0146] In this embodiment, the material was prepared with a crosslinking density of 1×10⁻ by adjusting the molar ratio of the prepolymer to the chain extender. 4 The material has a mol / cm³ content, and all other parameters are completely consistent with the best embodiment.

[0147] Test results: Cold flow rate 0.49%, no settling after 12 months, and performance retention rate 94.2% after 1000 cycles, meeting the core performance requirements of this invention, proving that 1×10⁻ 4 mol / cm³ is the effective lower limit endpoint for achieving the purpose of the invention.

[0148] Example 19 (corresponding to the verification of the crosslinking density upper limit technical solution in claim 1) This embodiment verifies the crosslinking density of 5×10⁻ in claim 1. 4 The upper limit technical solution of mol / cm³ can achieve the core technical effect of this invention.

[0149] In this embodiment, the material was prepared with a crosslinking density of 5×10⁻ by adjusting the molar ratio of the prepolymer to the chain extender. 4 The material has a mol / cm³ content, and all other parameters are completely consistent with the best embodiment.

[0150] Test results: Shear thickening factor 260 times, cold flow rate 0.32%, performance retention rate 92.1% after aging at 80℃, meeting the core performance requirements of this invention, proving that 5×10⁻ 4 mol / cm³ is the effective upper limit for achieving the purpose of the invention.

[0151] Example 20 (corresponding to the verification of the lower limit of stirring speed and upper limit of stirring time in claim 13) This embodiment verifies the lower / upper limit technical solution of stirring speed of 2000 rpm, stirring time of 3 h, and ultrasonic dispersion time of 40 min in step S3 of claim 13, and can achieve the core technical effect of the present invention.

[0152] In the preparation method of this embodiment, step S3 involves stirring at 2000 rpm for 3 hours, followed by ultrasonic dispersion for 40 minutes. The remaining formulation and process parameters are completely consistent with those of the best embodiment.

[0153] Performance test results: The shear thickening dispersion system was uniform and free of agglomeration. The final product had a shear thickening factor of 310 times and a cold flow rate of 0.42%. The remaining performance was consistent with the best embodiment, meeting the core performance requirements of the present invention. This proves that the stirring speed of 2000 rpm, the stirring time of 3 h, and the ultrasonic dispersion time of 40 min are the effective lower / upper limits for achieving the purpose of the invention.

[0154] Example 21 (corresponding to the verification of the upper limit of stirring speed and the lower limit of stirring time in claim 13) This embodiment verifies the upper / lower limit technical solution of stirring speed of 4000 rpm, stirring time of 1 h, and ultrasonic dispersion time of 20 min in step S3 of claim 13, and can achieve the core technical effect of the present invention.

[0155] In the preparation method of this embodiment, step S3 involves stirring at 4000 rpm for 1 hour, followed by ultrasonic dispersion for 20 minutes. The remaining formulation and process parameters are completely consistent with those of the best embodiment.

[0156] Performance test results: The shear thickening dispersion system was uniform and free of agglomeration. The final product had a shear thickening factor of 315 times and a cold flow rate of 0.41%. The remaining performance was consistent with the best embodiment, meeting the core performance requirements of the present invention. This proves that the stirring speed of 4000 rpm, the stirring time of 1 h, and the ultrasonic dispersion time of 20 min are the effective upper / lower limits for achieving the purpose of the invention.

[0157] Example 22 (corresponding to the verification of the lower limit of vacuum degree and upper limit of degassing time technical solutions in claims 14 and 15) This embodiment verifies the lower / upper limits of the vacuum degree of -0.08MPa, degassing time of 20min, hot pressing temperature of 120℃, hot pressing pressure of 8MPa, and hot pressing time of 60min in step S4 of claims 14 and 15, and can achieve the core technical effect of the present invention.

[0158] In the preparation method of this embodiment, step S4 involves degassing in stages for 20 minutes under a vacuum of -0.08 MPa. After degassing, the mixture is poured into a mold and hot-pressed for crosslinking at 120°C and 8 MPa for 60 minutes. The remaining formulation and process parameters are completely consistent with those of the best embodiment.

[0159] Performance test results: The product has no bubble defects, the interpenetration degree of the double network is 42%, and the crosslinking density is 2.9×10⁻ 4 The mol / cm³, shear thickening factor of 295 times, and cold flow rate of 0.45% meet the core performance requirements of this invention, proving that -0.08MPa vacuum, 20min degassing time, 120℃ hot pressing temperature, 8MPa hot pressing pressure, and 60min hot pressing time are the effective lower / upper limits for achieving the purpose of the invention.

[0160] Example 23 (corresponding to the verification of the upper limit of vacuum degree and lower limit of degassing time technical solutions in claims 14 and 15) This embodiment verifies the upper / lower limits of the technical solutions in step S4 of claims 14 and 15, namely, vacuum degree -0.1MPa, degassing time 10min, hot pressing temperature 140℃, hot pressing pressure 12MPa, and hot pressing time 30min, and can achieve the core technical effect of the present invention.

[0161] In the preparation method of this embodiment, step S4 involves degassing in stages for 10 minutes under a vacuum of -0.1 MPa. After degassing, the mixture is poured into a mold and hot-pressed for crosslinking at 140°C and 12 MPa for 30 minutes. The remaining formulation and process parameters are completely consistent with those of the best embodiment.

[0162] Performance test results: The product has no bubble defects, the interpenetration degree of the double network is 68%, and the crosslinking density is 3.1×10⁻ 4 The mol / cm³, shear thickening factor of 288 times, and cold flow rate of 0.43% meet the core performance requirements of this invention, proving that -0.1MPa vacuum, 10min degassing time, 140℃ hot pressing temperature, 12MPa hot pressing pressure, and 30min hot pressing time are the effective upper / lower limits for achieving the purpose of the invention.

[0163] Example 24 (corresponding to the verification of the lower limit of the curing temperature and the upper limit of the curing time in claim 16) This embodiment verifies the lower / upper limit technical solution of the curing temperature of 50°C and the curing time of 24h in step S5 of claim 16, and can achieve the core technical effect of the present invention.

[0164] In the preparation method of this embodiment, after cooling and demolding in step S5, the product is cured at a constant temperature of 50°C for 24 hours. The remaining formula and process parameters are completely consistent with those of the best embodiment.

[0165] Performance test results: The product is fully cross-linked, with a double-network interpenetration degree of 53% and a cross-linking density of 2.9 × 10⁻⁻⁻⁶. 4 The mol / cm³, shear thickening factor of 312 times, and cold flow rate of 0.42% are consistent with the best embodiment, meeting the core performance requirements of the present invention. This proves that the 50℃ curing temperature and 24h curing time are the effective lower / upper limits for achieving the purpose of the invention.

[0166] Example 25 (corresponding to the verification of the upper limit of the curing temperature and the lower limit of the curing time in claim 16) This embodiment verifies the upper / lower limit technical solution of the curing temperature of 70℃ and curing time of 12h in step S5 of claim 16, and can achieve the core technical effect of the present invention.

[0167] In the preparation method of this embodiment, after cooling and demolding in step S5, the product is cured at a constant temperature of 70°C for 12 hours. The remaining formula and process parameters are completely consistent with those of the best embodiment.

[0168] Performance test results: The product is fully cross-linked, with a double-network interpenetration degree of 56% and a cross-linking density of 3.1×10⁻ 4The mol / cm³, shear thickening factor of 313 times, and cold flow rate of 0.41% are consistent with the best embodiment, meeting the core performance requirements of the present invention. This proves that the 70℃ curing temperature and 12h curing time are the effective upper / lower limits for achieving the purpose of the invention.

[0169] Example 26 (corresponding to the verification of the polyurethane / epoxy resin blend system technical solution in claim 6) This embodiment verifies the technical solution of claim 6, which states that the covalent cross-linked chemical network is a polymer blend, and can achieve the core technical effect of the present invention.

[0170] In this embodiment, the covalently cross-linked chemical network is a polyurethane / epoxy resin blend cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 6 parts polyurethane prepolymer, 6 parts epoxy resin prepolymer, 3.75 parts 1,4-butanediol, 3.75 parts diethylenetriamine, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 5.8:1, which falls within the range of 5:1 to 10:1.

[0171] Preparation method: The surface modification of S1 nanoparticles is completely consistent with the best embodiment; the preparation of S2 premixed system is completely consistent with the best embodiment; S3 dual-network in-situ crosslinking: polyurethane prepolymer, epoxy resin prepolymer, 1,4-butanediol, diethylenetriamine and shear thickening dispersion system are mixed evenly, and the dry mass ratio of physical shear thickening network to covalent crosslinking chemical network is controlled at 5.8:1; degassing is performed in stages for 15 min under a vacuum of -0.1 MPa, the entire degassing process is kept at a constant temperature of 25℃, and the degassing stirring rate is 80 rpm; after degassing, it is poured into a flat mold and hot-pressed for crosslinking at 130℃ and 10 MPa for 45 min. The dual-network crosslinking and curing is completed in situ simultaneously through a one-step hot-pressing method, resulting in an interpenetration degree of 54% and a crosslinking density of 2.9 × 10⁻⁻⁻⁶. 4 Material with mol / cm³; S4 post-treatment: after cooling to room temperature, demold and mature in a constant temperature oven at 60℃ for 18 hours to obtain the finished product.

[0172] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 305 times, the cold flow rate is 0.43%, the performance retention rate after aging at 80℃ is 91.7%, and the self-healing efficiency is 84% ​​after 24 hours, proving that the polyurethane / epoxy resin blend system can fully achieve the core technical effects of this invention.

[0173] Example 27 (corresponding to the verification of the polyurethane / polysiloxane blend system technical solution in claim 6) This embodiment verifies the technical solution of claim 6, which states that the covalent cross-linked chemical network is a polymer blend, and can achieve the core technical effect of the present invention.

[0174] The material in this embodiment has a covalently cross-linked chemical network of polyurethane / polysiloxane blend cross-linked network. The formulation, by weight, totals 100 parts: 40 parts polyethylene glycol, 30 parts surface-modified mesoporous nano silica, 6 parts polyurethane prepolymer, 6 parts polysiloxane prepolymer, 3.75 parts 1,4-butanediol, 3.75 parts tetraethyl orthosilicate, 0.1 parts dibutyltin dilaurate, and 2 parts silane coupling agent KH550. The dry mass ratio of the physical network to the chemical network is 5.8:1, which falls within the range of 5:1 to 10:1.

[0175] The preparation method is completely consistent with that of Example 26.

[0176] Performance test results: at a shear rate of 1000s⁻¹, the shear thickening factor is 298 times, the cold flow rate is 0.44%, the performance retention rate after aging at 80℃ is 91.3%, and the self-healing efficiency is 83% after 24 hours, proving that the polyurethane / polysiloxane blend system can fully achieve the core technical effects of this invention.

[0177] Critical numerical comparison (verifying the inventiveness of the numerical range of the claims) To verify the criticality of the numerical ranges in the claims of this invention, the following comparative examples were set up, with all other raw materials and test conditions being completely consistent with the preferred embodiment: Comparative Example 1 (dry mass ratio 4:1, exceeding the lower limit): The dry mass ratio of the physical network to the chemical network was 4:1, and the rest of the formulation was consistent with the best embodiment. Test results: Shear thickening factor was 182 times, and cold flow rate was 1.2%, which failed to meet the core performance requirements, proving that 5:1 is the critical lower limit for achieving the purpose of the invention.

[0178] Comparative Example 2 (dry mass ratio 11:1, exceeding the upper limit): The dry mass ratio of the physical network to the chemical network was 11:1, and the rest of the formulation was the same as the best example. Test results: Shear thickening factor 225 times, cold flow rate 0.8%, slight sedimentation occurred after 6 months of storage, which could not meet the long-term stability requirements, proving that 10:1 is the critical upper limit for achieving the purpose of the invention.

[0179] Comparative Example 3 (interpenetration 30%, exceeding the lower limit): The interpenetration of the two networks was 30%, and the rest of the formulation was the same as the best embodiment. Test results: Shear thickening factor was 210 times, cold flow rate was 0.9%, and obvious phase separation occurred between the two phases, making it impossible to achieve the synergistic effect of the dual continuous interpenetrating structure, proving that 40% is the critical lower limit for achieving the purpose of the invention.

[0180] Comparative Example 4 (interpenetration 80%, exceeding the upper limit): The interpenetration of the dual networks was 80%, and the rest of the formulation was the same as the best embodiment. Test results: The shear thickening factor was 175 times. Excessive entanglement of the chemical network restricted the free movement of nanoparticles, and the shear thickening effect was significantly reduced, proving that 70% is the critical upper limit for achieving the purpose of the invention.

[0181] Comparative Example 5 (crosslinking density 0.5 × 10⁻) 4 (mol / cm³, exceeding the lower limit): Crosslinking density 0.5×10⁻ 4 The concentration was mol / cm³, and the rest of the formulation was consistent with the best embodiment. Test results: cold flow rate 1.5%, sedimentation occurred after 3 months, indicating insufficient structural support and inability to meet long-term stability requirements, proving that 1×10⁻ 4 mol / cm³ is the critical lower limit for achieving the purpose of the invention.

[0182] Comparative Example 6 (crosslinking density 6×10⁻) 4 mol / cm³ (exceeding the upper limit): Crosslinking density 6×10⁻ 4 mol / cm³, with the remaining formulation consistent with the best embodiment. Test results: Shear thickening factor of 220-fold, excessive cross-linking of the chemical network, limiting shear-induced aggregation of nanoparticles, and a significant decrease in protective performance, proving that 5×10⁻ 4 mol / cm³ is the critical upper limit for achieving the purpose of the invention.

[0183] In summary, any one of the polyurethane, epoxy resin, polysiloxane, and polyacrylate as defined in claim 1 of this invention, or their blends, or modified products that retain crosslinkable reactive groups after grafting / copolymerization / block modification, have corresponding examples to verify that they can achieve the core technical effects of this invention. The superior generalization of the claims is fully supported by the specification.

[0184] The core structural features of the 5:1 to 10:1 dry mass ratio range, non-covalent bonded interfacial bonding, and a maximum size of less than 100 nm in the two-phase dispersed phase region under a 5000x scanning electron microscope, as defined in claim 1, can achieve the core technical effects of this invention with all values, any sub-ranges, and all optional embodiments within this range; wherein the 50% to 60% interpenetration range and 2×10⁻⁻⁶ interpenetration range defined in claim 2 are also included. 4 mol / cm³~4×10⁻ 4 The crosslinking density range in mol / cm³ is verified by corresponding examples, which can achieve the core technical effect of the present invention; all additional technical features of claims 3-9 of the present invention are verified by corresponding examples, which can achieve the expected technical effect; all process steps and parameter ranges defined in claims 10-17 of the method of the present invention are verified by corresponding examples, which can achieve the core technical effect of the present invention; all technical features of claims 18-20 of the article of the present invention are verified by corresponding examples, which can achieve the expected technical effect; the protection scope of all claims is fully supported by the specification and complies with the provisions of Article 26, Paragraph 4 of the Patent Law of the People's Republic of China.

[0185] Comparative experiments and mechanistic explanations of synergistic effects Mechanism Explanation: The dual continuous interpenetrating physical network and chemical network form a synergistic effect. The physical network provides shear thickening protection properties, while the chemical network provides structural support and long-term stability. The two are bonded together through non-covalent bonds to form an interface, which not only ensures the free movement and aggregation of nanoparticles and achieves high shear thickening performance, but also restricts particle sedimentation and material cold flow through the three-dimensional support of the chemical network, thus achieving high protection performance and high stability.

[0186] To verify the inventiveness and unexpected technical effects of this invention, four sets of control experiments were set up. The raw materials, testing environment, and testing methods of all experiments were completely identical, with the only variable being the network structure of the material: Control group A: a purely physical dispersion system with no chemical cross-linking network, which adopts the technical solution closest to the existing technology CN115386340B. Control group B: Single cross-linked network structure, the chemical network is a discontinuous phase, and the technical solution of existing technology US11230728B2 is adopted completely; Control group C: A control scheme that is easy for those skilled in the art to conceive of, using a double continuous interpenetrating network structure, but the nanoparticles are not surface modified and there is no non-covalent bond interface between them and the chemical network. The other parameters are completely consistent with the preferred embodiment of the present invention. Experimental group: The best embodiment of the present invention.

[0187] The test results are as follows: Control group A: Shear thickening factor 195-fold, cold flow rate 8.72%, obvious stratification after 12 months of storage, and performance retention rate of 78% after 1000 cycles; Control group B: Shear thickening factor 85 times, cold flow rate 1.25%, no sedimentation after 12 months of storage, and performance retention rate of 82% after 1000 cycles; Control group C: Shear thickening factor 162-fold, cold flow rate 2.18%, slight sedimentation after 12 months of storage, and performance retention rate of 85% after 1000 cycles; Experimental group: shear thickening factor 318 times, cold flow rate 0.42%, no sedimentation after 12 months of storage, and 96% performance retention rate after 1000 cycles.

[0188] Experimental conclusion: Compared with the closest prior art control group A, the present invention has a 63% increase in shear thickening factor and a more than 94% decrease in cold flow rate, achieving a significant performance improvement; Compared with control group C, which is easily thought of by those skilled in the art, the present invention, through the synergistic effect of "double continuous interpenetrating network structure + non-covalent bond interface combination", increases the shear thickening factor by 96% and reduces the cold flow rate by more than 80%, proving that the technical solution of the present invention is not a conventional technical choice in the field and achieves technical effects that those skilled in the art could not have expected. This invention breaks through the technical bias in the field. While introducing a continuous chemical cross-linking network, it significantly improves the shear thickening performance and completely overcomes the cognitive limitations of the prior art.

Claims

1. A dynamic dual-network shear-thickening protective material, comprising a shear-thickening dispersion system and a polymer crosslinking matrix, wherein the shear-thickening dispersion system comprises nanoparticles with active hydroxyl groups on their surface and a polar dispersion medium; Its features are: The material has a dual continuous interpenetrating polymer network structure, which includes a three-dimensional continuous physical shear thickening network and a three-dimensional continuous covalent cross-linked chemical network that are interpenetrating and entangled. Both networks are three-dimensional continuous phases that run through the entire material, without any encapsulated or encapsulated island structures. The maximum size of the dispersed phase regions of the two phases is less than 100 nm, and there is no phase separation phenomenon. The active hydroxyl groups on the surface of nanoparticles in the physical shear thickening network are bonded to the polymer molecular chains of the covalently cross-linked chemical network through non-covalent bonds. The non-covalent bonds include at least one of hydrogen bonds, van der Waals forces, coordination bonds, and dipole interactions. The interfacial bonding allows the nanoparticles to freely undergo shear-induced aggregation under shearing action, while inhibiting nanoparticle sedimentation and material cold flow. The dry mass ratio of the physical shear thickening network to the covalently cross-linked chemical network is 5:1 to 10:1; The material has a double-network interpenetration degree of 40%–70% and a crosslinking density of 1×10⁻ ... 4 mol / cm³~5×10⁻ 4 mol / cm³.

2. The dynamic dual-network shear-thickening protective material according to claim 1, characterized in that, The material has a double-network interpenetration degree of 50%–60% and a crosslinking density of 2 × 10⁻ ... 4 mol / cm³~4×10⁻ 4 mol / cm³.

3. The dynamic dual-network shear-thickening protective material according to claim 2, characterized in that, The material has a double-network interpenetration degree of 55% and a crosslinking density of 3×10⁻⁻⁻⁻⁶. 4 mol / cm³.

4. The dynamic dual-network shear-thickening protective material according to claim 1, characterized in that, The polar dispersion medium is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether glycol, or a mixed system formed by the above polyether and functional additives; the functional additives are at least one of antioxidants, ultraviolet absorbers, flame retardants, and anti-aging agents, and the amount added is 0.05% to 1% of the mass of the polar dispersion medium.

5. The dynamic dual-network shear-thickening protective material according to claim 1, characterized in that, The nanoparticles are at least one of the following: mesoporous nano-silica, nano-alumina, nano-calcium carbonate, nano-montmorillonite, and nano-zinc oxide with active hydroxyl groups on the surface; the nanoparticles are surface modified with a silane coupling agent, and the surface hydroxyl content of the modified nanoparticles is ≥2 mmol / g.

6. The dynamic dual-network shear-thickening protective material according to claim 1, characterized in that, The covalent crosslinked chemical network is any one of polyurethane, epoxy resin, polysiloxane, and polyacrylate, or a blend of two or more of the above polymers, or a modified product obtained by grafting / copolymerizing / block modifying the above polymers or blends with epoxy, amino, or vinyl groups, retaining crosslinkable reactive groups and capable of forming a three-dimensional continuous covalent crosslinked network.

7. The dynamic dual-network shear-thickening protective material according to any one of claims 1 to 6, characterized in that, The test was conducted using a rotational rheometer with a parallel plate fixture at 25℃ and 50% relative humidity, with a test gap of 1 mm. The steady-state shear rate range was 0.1–10. 4 The shear thickening factor at a shear rate of 1000 s⁻¹ is ≥260 times, where the shear thickening factor is the ratio of the maximum apparent viscosity to the zero shear viscosity at that shear rate.

8. The dynamic dual-network shear-thickening protective material according to any one of claims 1 to 6, characterized in that, At 25℃, the cold flow rate is ≤0.5% under the conditions of 24h test according to HG / T 3871-2008 standard and 1kg load.

9. The dynamic dual-network shear-thickening protective material according to claim 7, characterized in that, At 25℃, the cold flow rate is ≤0.5% under the conditions of 24h test according to HG / T 3871-2008 standard and 1kg load.

10. A method for preparing a dynamic dual-network shear-thickening protective material, used to prepare the dynamic dual-network shear-thickening protective material according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Nanoparticle surface modification: Nanoparticles with active hydroxyl groups on their surface are modified to obtain modified nanoparticles with a surface hydroxyl content ≥2mmol / g. S2: Preparation of cross-linked matrix prepolymer: Preparation of polymer prepolymers for forming covalent cross-linked chemical networks; S3: Preparation of premixed system: Modified nanoparticles are dispersed in a polar dispersion medium to obtain a uniform shear-thickening dispersion system; S4: Dual-network in-situ crosslinking: The polymer prepolymer, the corresponding curing system, and the shear-thickening dispersion system are mixed evenly, and the dry mass ratio of the physical shear-thickening network to the covalent crosslinking chemical network is controlled to be 5:1 to 10:

1. After degassing, in-situ simultaneous crosslinking is performed in one step, that is, through a single hot-pressing process, hot-pressing is performed at 120 to 140°C and 8 to 12 MPa for 30 to 60 minutes, simultaneously completing the hydrogen bond crosslinking of the physical shear-thickening network and the covalent bond curing of the covalent crosslinking chemical network, and simultaneously forming an interpenetrating and entangled dual continuous three-dimensional interpenetrating network structure. S5: Post-processing: After cooling and demolding, the material is cured to obtain the dynamic dual-network shear-thickening protective material; The execution order of steps S1 and S2 can be arbitrary, synchronous, or interchangeable.

11. The preparation method according to claim 10, characterized in that, Step S1 specifically involves: dispersing nanoparticles with active hydroxyl groups on their surface in an alcohol dispersion medium to prepare a dispersion with a nanoparticle mass fraction of 8%–12%; adding 1%–3% of a silane coupling agent by mass of the nanoparticles; adjusting the pH of the system to 4–5; stirring and reacting at 60–80°C for 3–5 hours; separating, washing, and drying to obtain modified nanoparticles with a surface hydroxyl content ≥2 mmol / g; wherein the silane coupling agent is selected from at least one of aminosilane, epoxysilane, and vinylsilane.

12. The preparation method according to claim 10, characterized in that, In step S2, the polymer prepolymer is any one of polyurethane prepolymer, epoxy resin prepolymer, polysiloxane prepolymer, and polyacrylate prepolymer.

13. The preparation method according to claim 10, characterized in that, Step S3 specifically involves dispersing the modified nanoparticles in a polar dispersion medium, stirring at 2000–4000 rpm for 1–3 hours, and then ultrasonically dispersing for 20–40 minutes to obtain a uniform shear-thickening dispersion system. The polar dispersion medium is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether glycol, or a mixed system formed by the above polyethers and functional additives.

14. The preparation method according to claim 10, characterized in that, In step S4, the degassing process is as follows: degassing is carried out in stages for 10 to 20 minutes under a relative vacuum of -0.08 MPa to -0.1 MPa, and the entire degassing process is carried out under a constant temperature of 20 to 30°C; the staged degassing is as follows: the first stage is degassing for 5 to 10 minutes under a relative vacuum of -0.08 MPa with a stirring speed of 80 to 100 rpm; the second stage is degassing for 5 to 10 minutes under a relative vacuum of -0.1 MPa with a stirring speed of 50 to 80 rpm.

15. The preparation method according to claim 10, characterized in that, In step S4, the in-situ crosslinking process is as follows: after degassing, the material is poured into a mold and hot-pressed for crosslinking at 120-140°C and 8-12MPa for 30-60 minutes to complete the one-step in-situ synchronous crosslinking.

16. The preparation method according to claim 10, characterized in that, Step S5 specifically involves: cooling to room temperature and then demolding, followed by constant temperature curing at 50–70°C for 12–24 hours to obtain the dynamic dual-network shear-thickening protective material.

17. The preparation method according to claim 10, characterized in that, The preparation method is a continuous preparation method, including the following steps: S1: Nanoparticle surface modification: Nanoparticles with active hydroxyl groups on the surface are dispersed in an alcohol dispersion medium to prepare a dispersion with a nanoparticle mass fraction of 8% to 12%. 1% to 3% of silane coupling agent by mass of nanoparticles is added, the pH of the system is adjusted to 4-5, and the reaction is stirred at 60 to 80°C for 3 to 5 hours. After separation, washing, and drying, modified nanoparticles with a surface hydroxyl content ≥2 mmol / g are obtained. S2: Preparation of cross-linked matrix prepolymer: Preparation of polymer prepolymers for forming covalent cross-linked chemical networks; S3: Continuous preparation of premixed system: The modified nanoparticles obtained in step S1 and the polar dispersion medium are continuously added to a twin-screw mixer in proportion and continuously mixed at a speed of 2000-4000 rpm for 1-3 hours, and simultaneously ultrasonically dispersed online for 20-40 minutes to obtain a uniform shear thickening dispersion system. S4: Dual-network in-situ continuous crosslinking: The polymer prepolymer obtained in step S2, the curing system matching the type of prepolymer, and the shear thickening dispersion system obtained in step S3 are continuously metered and mixed in proportion, controlling the dry mass ratio of the physical shear thickening network to the covalent crosslinking chemical network to be 5:1 to 10:1; continuous degassing is carried out for 10 to 20 minutes under a relative vacuum of -0.08 MPa to -0.1 MPa, and the entire degassing process is carried out under a constant temperature of 20 to 30°C, with the stirring rate controlled at 50 to 100 rpm during the degassing process; after degassing, the mixture is continuously coated onto the release substrate and sent to a continuous roller pressing production line, where it is hot-pressed and crosslinked for 30 to 60 minutes at 120 to 140°C and 8 to 12 MPa pressure. The hydrogen bond crosslinking of the physical shear thickening network and the covalent bond curing of the covalent crosslinking chemical network are completed simultaneously in situ through a one-step hot-pressing process, forming a dual continuous three-dimensional interpenetrating network structure; S5: Post-processing: The hot-pressed sheet is continuously fed into the cooling section to cool to room temperature, and after being wound up, it is cured at a constant temperature of 50-70℃ for 12-24 hours. After slitting, the dynamic double-network shear thickening protective material is obtained.

18. An impact protection product, characterized in that, The article comprises a protective functional layer, which is made of the dynamic dual-network shear-thickening protective material according to any one of claims 1 to 9, or is prepared by the preparation method according to any one of claims 10 to 17.

19. The impact protective product according to claim 18, characterized in that, The thickness of the protective functional layer is 0.5mm to 20mm.

20. The impact protective product according to claim 18, characterized in that, The impact protection products are any one of the following: sports protective gear, industrial cushioning pads, automotive anti-collision components, explosion-proof and impact-resistant products, police protective equipment, and aerospace cushioning components.

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