Organic-inorganic copolymerized high-impact-resistance elastomer composite material and preparation method thereof

Abstract

The invention discloses a high-impact-resistance elastomer composite material based on an organic-inorganic copolymerization strategy and a preparation method thereof. The composite material is prepared through an organic-inorganic copolymerization strategy and comprises metal oxide nanoparticles with the particle size of 1-10 nm and rich in unsaturated metal sites on the surface as an inorganic phase and a polymer network containing dynamic covalent bonds as an organic phase, the inorganic phase and the organic phase are connected through a chemical bond to form a molecular-scale organic-inorganic hybrid structure unit, so that uniform dispersion and strong interface combination of the inorganic phase are realized. The preparation method comprises the following steps: regulating and synthesizing zinc oxide nanoparticles with rich unsaturated sites on the surfaces through a regulator; carrying out pre-coordination assembly on the zinc oxide and a lipoic acid monomer to form a lipoic acid-zinc oxide hybrid monomer; and carrying out thermal polymerization to obtain the elastomer composite material. The elongation at break of the obtained material reaches 541% and is increased by nearly 12 times compared with that of pure polylipoic acid, the impact force can be attenuated by 90% or above in a drop hammer impact test, the impact strain rate reaching up to 4000 s <-1 > can be borne, and damage self-healing can be achieved at the room temperature without external force. The material has excellent impact resistance, high toughness, intrinsic self-healing ability and solvent-resistant stability, the preparation method is simple and controllable, and the material has wide application prospects in the fields of personal protection, aerospace, flexible electronics and the like.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a novel elastomeric composite material based on an organic-inorganic copolymerization strategy that possesses high impact resistance, high toughness, and self-healing function, and a method for its preparation. Background Technology

[0002] High-performance impact-resistant materials are the core foundation for ensuring personnel safety under extreme dynamic loads and maintaining the structural integrity of equipment in complex service environments. They possess indispensable strategic value in key areas such as personal protective equipment, vehicle armor, aerospace, and cushioning packaging for precision instruments. Traditional impact-resistant materials, such as high-strength steel, aluminum alloys, and engineering ceramics, primarily rely on high strength to resist deformation, but they generally suffer from inherent limitations such as high density, poor flexibility, and inability to self-recover after damage. To meet the demands of modern equipment for lightweight and flexibility, polymer-based impact-resistant materials have attracted significant attention due to their lightweight, high toughness, and excellent energy dissipation capabilities. However, single polymer materials often have insufficient modulus, making them prone to irreversible fracture under extreme impacts. Therefore, researchers have attempted to introduce metal oxide nanoparticles as rigid reinforcing phases to construct composite materials that combine rigidity and toughness.

[0003] However, the successful implementation of this strategy has long been limited by a core scientific challenge—the incompatibility of the organic-inorganic interface. Due to the significant differences in the surface chemical properties of polymers and metal oxides, nanoparticles are prone to agglomeration in the polymer matrix, forming stress concentration points. This not only weakens the reinforcing effect but also becomes a source of crack initiation during impact, leading to premature material failure. While existing interface control strategies have made contributions to addressing this problem, they all have limitations in terms of interfacial bonding strength, structural uniformity, or process controllability, making it difficult to fundamentally achieve uniform mixing and strong bonding of organic and inorganic components.

[0004] Based on this situation, the present invention provides a high impact-resistant elastomer composite material and its preparation method based on an organic-inorganic copolymerization strategy. By introducing a regulator to control the growth of metal oxides, a self-healing composite material with small particle size, good dispersibility and tight bonding with the organic matrix is ​​obtained, which can maintain a stable morphology under high-speed impact. Summary of the Invention

[0005] This invention proposes an organic-inorganic copolymerization strategy based on a "polymer monomer-metal oxide structural unit". This strategy selects polythiooctanoic acid (PHA), constructed from dynamic disulfide bonds, as the organic matrix, whose dynamic network inherently possesses energy dissipation capabilities. Simultaneously, zinc oxide nanoparticles with abundant unsaturated coordination sites on their surface are selected as the inorganic reinforcing phase. Pre-coordination assembly of zinc oxide and PHA monomers is achieved through a polymerization precursor, forming stable hybrid structural units linked by coordination bonds, ensuring interfacial strength and composite homogeneity. Controlled thermal polymerization then successfully constructs the PHA / ZnO molecular hybrid network. Mechanical and impact resistance tests demonstrate that this material exhibits excellent balance between stiffness and toughness, energy dissipation capabilities, and self-healing properties. This method is simple, widely applicable, and highly controllable, providing a novel approach for designing next-generation high-performance dynamic impact-resistant materials.

[0006] The technical solution adopted to achieve the purpose of this invention is: a high impact-resistant elastomer composite material based on an organic-inorganic copolymerization strategy and its preparation method, characterized in that the inorganic phase and the organic phase are connected by chemical coordination bonds or covalent bonds, specifically, the unsaturated metal sites on the surface of the metal oxide nanoparticles coordinate or react with carboxyl groups, thiol groups or amino groups on the monomers or polymer chains of the organic phase to form molecular-scale organic-inorganic hybrid structural units, thereby achieving uniform dispersion and strong interfacial bonding of the inorganic phase.

[0007] A method for preparing plant SOD enzyme with enhanced activity and stability, wherein the specific operation of the preparation method is as follows: plant SOD enzyme and ball milling beads are added to a centrifuge tube at room temperature, and then a ball milling reaction is carried out. After the reaction is completed, the mechanochemically modified plant SOD enzyme is obtained.

[0008] In some embodiments, the inorganic phase refers to metal oxide nanoparticles with a particle size of 1-10 nm and a surface rich in unsaturated metal sites, preferably zinc oxide (ZnO), and more preferably, a regulator to control the synthesis of ZnO nanoparticles with a surface rich in unsaturated zinc sites.

[0009] In some embodiments, the organic phase refers to a polymer network containing dynamic covalent bonds, preferably a polythioctic acid (PTA) network formed by ring-opening polymerization of thioctic acid (TA), in which disulfide bonds (SS) in the main chain endow the material with self-healing properties.

[0010] In some embodiments, the regulator is a type of low-boiling-point organic small molecule that has certain chemical interactions (such as hydrogen bonds, coordination bonds, and van der Waals forces) with metal ions of metal oxides or organic matrices. This can play a role in first capping and stabilizing the end before removing it to initiate further polymerization. Triethylamine is preferred.

[0011] In some embodiments, the preparation process of the polymer monomer-metal oxide structural unit involves dissolving zinc acetate dihydrate in methanol, adding a regulator diluent while stirring, mixing thoroughly, and then heating to react, resulting in a zinc oxide suspension. Lipoic acid is then dispersed in methanol, added to the above zinc oxide suspension for coordination assembly, and after concentration, washing, centrifugation, and freeze-drying, a lipoic acid-zinc oxide hybrid monomer is obtained.

[0012] In some embodiments, the preparation process of the elastomeric composite material generally involves filling polymer monomer-metal oxide structural unit powder into a customized silicone mold and pressing it, then heating and polymerizing it on a heating table to form an elastic block.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] 1. The advantages of this invention lie in the excellent impact resistance and energy absorption properties of the elastomeric composite material. A hybrid network combining rigidity (inorganic nanounits) and flexibility (dynamic polymer network) is constructed through organic-inorganic copolymerization. The rigid inorganic units act as physical crosslinking points and reinforcing phases, effectively transferring and dispersing stress; the flexible dynamic network dissipates a large amount of impact energy through chain segment movement and reversible breakage / reorganization of dynamic bonds. Examples show that the resulting material achieves an elongation at break of over 540% and can attenuate over 90% of the impact force in drop hammer impact tests.

[0015] 2. The advantage of this invention is that the prepared elastomer composite material has intrinsic self-healing ability. The dynamic disulfide bonds in the organic phase can undergo reversible exchange under external stimuli (such as heat and light), enabling the material to heal itself after microcracks are generated by impact, restore its mechanical integrity, and significantly extend its service life.

[0016] 3. The advantages of this invention lie in its strong interfacial bonding and uniform dispersion. The strategy of first coordinating and assembling, followed by controlled polymerization, ensures that inorganic nanoparticles are chemically bonded to the polymer network, fundamentally solving the problems of agglomeration and interfacial debonding, and achieving long-term stable dispersion of the inorganic phase.

[0017] 4. The advantages of this invention lie in its controllable preparation method and mild conditions. The entire preparation process is carried out in an aqueous phase or a mild organic solvent, requiring no demanding equipment. The mechanical properties and repair efficiency of the material can be easily controlled by adjusting the monomer ratio and polymerization conditions, making it suitable for large-scale preparation. Attached Figure Description

[0018] Figure 1 This is a flowchart of the preparation process of the present invention and a comparative schematic diagram with the traditional blending method;

[0019] Figure 2 High-resolution transmission electron microscopy (HRTEM) image of 3 nm ZnO nanoparticles prepared in Example 1;

[0020] Figure 3 PTA prepared in Example 2 s Comparison of stress-strain curves between ZnO composite materials, pure PTA, and PTA / ZnO blends.

[0021] Figure 4 The images show a comparison of the PTA5ZnO composite material prepared in Example 2 before and after high-speed impact testing, along with its stress-strain curves.

[0022] Figure 5 The image shows a macroscopic photograph of the self-healing process of the PTA5ZnO composite material in Example 3, along with a graph illustrating the recovery rate of mechanical properties after repair. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] Example 1

[0025] The synthesis of ZnO nanoparticles with surface-rich unsaturated zinc sites is achieved through the following steps:

[0026] First, weigh out 0.002 mol of zinc acetate dihydrate and dissolve it in 25 ml of methanol, and dilute 0.006 mol of triethylamine in 12.5 ml of methanol.

[0027] Triethylamine dilution was added dropwise to zinc acetate dihydrate dispersion under stirring at 500 rpm at room temperature. After the two were mixed evenly, the mixture was placed in a shaker at 60°C for two hours to obtain a semi-transparent colloidal solution.

[0028] After centrifugation, concentration, purification, and dispersion, HRTEM characterization showed that uniform ZnO nanoparticles were synthesized with an average particle size of 3.0 ± 0.5 nm.

[0029] The ZnO nanoparticles prepared in Example 1 are characterized in that: the ZnO nanoparticles are zinc oxide nanoparticles with surface-rich unsaturated zinc sites synthesized by triethylamine regulation. Figure 1 It can be seen that the average particle size is 3.0±0.5 nm, and it is in a uniformly dispersed semi-transparent colloidal state. High-resolution transmission electron microscopy (HRTEM) characterization shows that the nanoparticles have abundant unsaturated coordination sites on the surface, which can form strong coordination interactions with functional groups such as carboxyl groups in organic monomers, providing an active interface basis for the subsequent construction of molecular-scale organic-inorganic hybrid structural units.

[0030] Example 2

[0031] The PTA5ZnO high impact-resistant composite material is prepared through the following steps:

[0032] First, weigh 0.01 mol of α-lipoic acid and disperse it in 50 ml of methanol. Then, add the zinc oxide suspension dropwise and stir the mixture at room temperature for 4 hours to form a lipoic acid-zinc oxide copolymer.

[0033] Then, the mixture was concentrated by rotary evaporation at 35°C until it became a yellow, transparent gel. It was washed five times with deionized water, centrifuged at 10,000 rpm, and lyophilized for later use.

[0034] Zinc oxide thioctic acid monomer powder was filled into a silicone mold and pressed tightly. The mold was then heated at 140°C for 1 hour to form a translucent yellow block.

[0035] Comparative Example: Preparation of PTA / ZnO Physical Blends

[0036] First, weigh 0.01 mol of α-lipoic acid powder, heat it at 140℃ for 10 min, cool it to room temperature, and disperse it in 50 ml of methanol. Add zinc oxide suspension dropwise, and stir the mixture at room temperature for 4 hours to form polylipoic acid zinc oxide copolymer.

[0037] Then, it was concentrated by rotary evaporation at 35°C until it became a yellow, transparent gel. It was then washed five times with deionized water, centrifuged at 10,000 rpm for 5 minutes, and freeze-dried.

[0038] Finally, the freeze-dried powder is filled into a silicone mold and pressed tightly, then heated at 140°C for 1 hour to form a block.

[0039] Performance testing

[0040] Figure 3 Regarding mechanical properties, the PTA5ZnO material in Example 2 exhibits an elongation at break of 541% and a tensile strength of 0.21 MPa; while the comparative blend material has an elongation at break of only 6% and exhibits brittle fracture.

[0041] Figure 4 To assess high-speed impact resistance, the Hopkinson pressure bar (SHPB) simulates high-speed dynamic impact tests to evaluate the dynamic impact performance of composite materials. The SHPB mainly consists of an impact bar, an incident bar, and a drive bar. The test sample is a cylindrical sample with a diameter of 10 mm and a thickness of 2 mm. The high-speed bullet is driven by high-pressure gas generated by an air pump. A signal conditioner processes the signals from the incident bar and the drive bar. The material can withstand 4000 seconds of impact. -1 High-speed impact.

[0042] Figure 5 To demonstrate self-healing properties, after the PTA5ZnO film was cut, the fracture surface completely healed after 24 hours of no external force contact at room temperature; while the comparative material had no self-healing ability.

[0043] Example 3: Regulation of material composition and properties

[0044] Changing the mass ratio of TA monomer to ZnO (e.g., PTA) 10 A series of materials were prepared using ZnO (i.e., materials with higher ZnO content) according to the method in Example 2. Tests revealed that as the ZnO content increased, the material modulus and strength increased, but the elongation at break decreased. This indicates that by adjusting the composition, the strength-toughness balance of the material can be customized within a certain range to meet the needs of different impact resistance scenarios.

[0045] This invention is not limited to the specific embodiments described above. Those skilled in the art can make various substitutions and improvements to the types of metal oxides, organic dynamic polymers, coordinating groups, polymerization methods, etc., within the scope defined in the claims, and all of these fall within the protection scope of this invention.

Claims

1. A high-impact elastomer composite material based on an organic-inorganic copolymerization strategy, characterized in that, The composite material is a hybrid network material prepared by an organic-inorganic copolymerization strategy, comprising: inorganic phase metal oxide nanoparticles with a particle size of 1-10 nm and rich in unsaturated metal sites on their surface; and organic phase polymer network containing dynamic covalent bonds. The inorganic and organic phases are connected by chemical bonds to form molecular-scale organic-inorganic hybrid structural units, with the inorganic phase uniformly dispersed within the organic phase.

2. The composite material according to claim 1, characterized in that, The chemical bonds between the inorganic and organic phases are coordination bonds or covalent bonds, specifically formed by the coordination or reaction between the unsaturated metal sites on the surface of the metal oxide nanoparticles and the carboxyl, thiol, or amino groups on the monomers or polymer chains of the organic phase.

3. The composite material according to claim 1 or 2, characterized in that, The inorganic phase is zinc oxide (ZnO), preferably zinc oxide nanoparticles with surface-rich unsaturated zinc sites synthesized by regulating agents.

4. The composite material according to claim 3, characterized in that, The regulator is a low-boiling-point organic molecule that has chemical interaction with metal ions or an organic matrix, preferably triethylamine.

5. The composite material according to claim 1, characterized in that, The organic phase is a polythioctic acid (PTA) network formed by the ring-opening polymerization of thioctic acid (TA), and its main chain contains dynamic disulfide bonds.

6. A method for preparing a high-impact elastomer composite material as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Preparation of zinc oxide precursor: Dissolve the zinc source in a solvent, add a regulator while stirring, mix well and heat to react, to obtain a zinc oxide suspension rich in unsaturated zinc sites; Step 2: Preparation of lipoic acid-zinc oxide hybrid monomer: Lipoic acid is dissolved in a solvent and added to the zinc oxide suspension obtained in Step 1 for coordination assembly. After post-processing, lipoic acid-zinc oxide hybrid monomer powder is obtained. Step 3: Molding of the elastomer composite material: The hybrid monomer powder obtained in step 2 is filled into a mold and heated to polymerize, thereby obtaining a high-impact elastomer composite material.

7. The method according to claim 6, characterized in that, The zinc source in step 1 is zinc acetate dihydrate, the solvent is methanol, the regulator is triethylamine, the reaction temperature is 50-70℃, and the reaction time is 1-3 hours.

8. The method according to claim 6, characterized in that, The coordination assembly described in step 2 is stirred at room temperature for 2-6 hours, and the post-processing includes concentration, washing, centrifugation and freeze drying.

9. The method according to claim 6, characterized in that, The heating polymerization temperature in step 3 is 110-160℃, and the polymerization time is 0.5-2 hours.

10. The method according to claim 6, characterized in that, The mechanical properties and crosslinking density of the resulting composite material can be controlled by adjusting the molar ratio of lipoic acid to zinc oxide in step 2 or the polymerization temperature in step 3.

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