Environment-friendly low-noise automobile rubber damping part and manufacturing process thereof

Abstract

The invention relates to the technical field of polymer composite materials, and discloses an environment-friendly low-noise automobile rubber damping part and a manufacturing process thereof.The damping part is made of a rubber composite material, and the rubber composite material comprises a dynamic reversible cross-linked rubber matrix, an anti-aging agent, an anti-aging agent and an anti-aging agent. A nanofiller having a core-shell structure; wherein the dynamic reversible cross-linked rubber matrix comprises the following components in parts by mass: 100 parts of furan functionalized epoxidized natural rubber; 3 to 8 parts by mass of bimaleimide; the content of the nanofiller with the core-shell structure is 5-20 parts by mass. By introducing the specially designed core-shell structure nanofiller, an innovative interface friction energy dissipation mechanism is constructed in the material, and the mechanism and the viscoelastic internal friction of a rubber matrix have a synergistic effect to form a dual energy dissipation way, so that vibration energy can be more efficiently absorbed and converted, and the energy dissipation efficiency is improved. And the excellent damping characteristic is shown under a wide working condition.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to an environmentally friendly, low-noise automotive rubber shock absorber and its manufacturing process. Background Technology

[0002] Vibration damping and noise reduction materials are key functional materials for controlling vibration and noise, improving equipment operational stability and driving comfort, and play a vital role in the automotive industry, rail transportation, aerospace, and precision instrument manufacturing. High-elasticity rubber materials, due to their unique viscoelastic properties, have become the most widely used and technologically mature choice in this field.

[0003] Currently, mainstream high-performance rubber shock absorbers are generally made from traditional thermosetting rubbers, such as natural rubber and styrene-butadiene rubber. These materials, through vulcanization, form a stable and permanent three-dimensional chemical cross-linked network between the rubber macromolecular chains. This thermosetting chemical structure endows them with excellent mechanical properties and durability, but it also fundamentally means that they cannot be melted down and reshaped after disposal. Whether it's scraps generated during production or waste products that have reached the end of their service life, they are difficult to effectively recycle and reuse, and are usually only subjected to incineration or low-value physical crushing and landfilling. This not only causes a huge waste of resources, but their non-degradable characteristics also lead to an increasingly serious "black pollution" problem.

[0004] Meanwhile, existing technologies also face challenges in pursuing high-performance vibration reduction and noise reduction. There is often an inherent contradiction between high elasticity and high damping performance; conventional high-elasticity rubber has a limited damping coefficient. Although adding traditional fillers such as carbon black and silica can improve the damping performance of materials to some extent, their energy dissipation mechanism is relatively simple, mainly relying on the internal friction of rubber molecular chains and the interaction between the filler and the matrix. This often fails to meet the stringent requirements of modern high-end equipment for efficient damping performance across a wide temperature and frequency range, and its performance improvement potential has reached a bottleneck.

[0005] Furthermore, the reliability and lifespan of traditional vulcanized rubber are limited during long-term service. Under cyclic loading, fatigue, or accidental physical damage, microcracks generated within the material will continue to propagate, eventually leading to macroscopic failure of the component. Its permanent chemical network structure lacks any inherent damage repair capability; once damaged, it is permanent. This not only shortens the effective service life of components but also increases maintenance costs and potential safety risks. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an environmentally friendly, low-noise automotive rubber shock absorber and its manufacturing process, solving the comprehensive technical defects of existing high-performance shock absorber rubbers, such as the inability to recycle and reuse them due to their permanent cross-linked networks, the limitation of their damping performance due to their single energy dissipation mechanism, and the lack of self-repair capabilities.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an environmentally friendly, low-noise automotive rubber shock absorber, wherein the shock absorber is made of a rubber composite material, and the rubber composite material comprises the following components: Dynamically reversibly crosslinked rubber matrix; Core-shell structured nanofillers; The dynamically reversibly crosslinked rubber matrix comprises: Furan-functionalized epoxidized natural rubber: 100 parts by weight; Bimaleimide: 3-8 parts by weight; The content of the core-shell structured nanofiller is 5-20 parts by weight; Specifically, the dynamically reversibly cross-linked rubber matrix is ​​the chemical basis for achieving the "environmentally friendly" characteristics (i.e., recyclability and self-healing) of this shock absorber. It consists of furan-functionalized epoxidized natural rubber (100 parts by mass) as the main polymer and bimaleimide (3-8 parts by mass) as the cross-linking agent. The furan functional groups act like "active hooks" pre-installed on the rubber macromolecular chains, while the bimaleimide molecules act as bidirectional "locks." At a certain temperature, the two connect the originally independent rubber chains into a complete three-dimensional network through a reversible Diels-Alder reaction, giving the shock absorber excellent mechanical strength and high elasticity. The amount of bimaleimide is precisely controlled within the range of 3-8 parts by mass, which is crucial to ensuring the formation of an effective network density, thereby obtaining ideal mechanical properties and durability; too little dosage results in insufficient cross-linking and performance degradation, while too much dosage makes the material too hard and brittle.

[0008] Furthermore, to achieve its core function of "low noise," the composite material incorporates 5-20 parts by weight of a core-shell structured nanofiller. This filler is not a simple reinforcing agent in the traditional sense; its structure is precisely designed to create a novel physical damping mechanism. When a car vibrates during driving, a microscopic relative motion occurs between the high-rigidity core inside the filler and the relatively soft rubber matrix surrounding it. The flexible shell layer encasing the core acts as a controlled "sliding interface," efficiently converting a large amount of vibrational mechanical energy into heat energy and dissipating it through interfacial friction during this microscopic motion. This "interfacial friction energy dissipation" mechanism complements the viscoelastic internal friction of the rubber matrix itself, thereby enabling the shock absorber to exhibit damping performance far exceeding that of traditional materials. The content of this filler is also optimized between 5-20 parts by weight to achieve the best balance between significantly improving the damping effect and maintaining the material's excellent overall mechanical properties and processability.

[0009] Preferably, the furan-functionalized epoxidized natural rubber is prepared from natural rubber through epoxidation and furan group grafting reaction.

[0010] Preferably, the core-shell structured nanofiller comprises: A core composed of crystalline nanocellulose; A shell layer made of polysiloxane covering the surface of the core.

[0011] Preferably, the polysiloxane shell and the crystalline nanocellulose core are connected by chemical bonds.

[0012] A manufacturing process for an environmentally friendly, low-noise automotive rubber shock absorber includes the following steps: S1: Mixing: Furan-functionalized epoxidized natural rubber, core-shell structured nanofillers, and bimaleimide are mixed under conditions below the dissociation temperature of the dynamic reversible crosslinking system to obtain a premix; Furthermore, this step aims to uniformly and physically disperse all components to prepare a stable and readily processable intermediate. Furan-functionalized epoxidized natural rubber as the matrix, core-shell nanofillers acting as key damping agents, and bimaleimide as a crosslinking agent are added together into a standard rubber mixing apparatus such as an internal mixer or open mill. The key to this operation is that the temperature throughout the mixing process must be strictly controlled below the dissociation temperature of the dynamically reversible crosslinking system (typically below 90°C). Under these low-temperature conditions, the Diels-Alder reaction is not activated, ensuring that the bimaleimide crosslinking agent is uniformly dispersed physically in the rubber matrix, rather than undergoing premature chemical crosslinking. The final result is a homogeneous and stable solid premix with an appearance and feel similar to conventional uncured rubber compounds, which can be stored at room temperature for extended periods without affecting subsequent processing properties.

[0013] S2: Molding: The premix is ​​placed in a mold, heated and pressurized under conditions higher than the dissociation temperature of the dynamic reversible crosslinking system, so that the premix melts and fills the mold; Furthermore, this is the core step in transforming the premix into the final product shape, fully utilizing the thermoplastic behavior of the material. The premix obtained in step S1 is placed in a mold of a predetermined shape (such as an injection molding machine or compression molding machine). Subsequently, the mold is rapidly heated to a temperature far above the dissociation temperature of the dynamically reversible crosslinked system (typically between 120-150°C). At this high temperature, a crucial "de-crosslinking" transformation occurs within the material: the previously latent Diels-Alder chemical bonds undergo reversible dissociation, the three-dimensional network structure temporarily opens, and the solid rubber transforms into a viscous melt with good flowability. When pressure is applied at this point, the melt, like thermoplastic, can rapidly and seamlessly fill every fine structure of the mold, thereby precisely replicating the complex shape of the shock absorber.

[0014] S3: Shaping: Cool the mold to a temperature below the dissociation temperature of the dynamic reversible crosslinking system, so that the premix is ​​solidified and formed in the mold; Furthermore, this step is the final stage in "locking in" the product form and restoring its high-performance rubber properties. While maintaining pressure, the mold is actively cooled, causing its temperature to drop rapidly to well below the dissociation temperature of the dynamically reversible crosslinking system (e.g., below 60°C). As the temperature decreases, the thermodynamic equilibrium of the system shifts in a direction favorable to crosslinking, and the dissociated furan and maleimide functional groups spontaneously undergo a Diels-Alder reaction again, rapidly and uniformly rebuilding a stable three-dimensional covalent network throughout the material. This process is a rapid physical solidification process, rather than a lengthy chemical reaction. Once the network reconstruction is complete, the material recovers from a molten state to a highly elastic solid state, and its final shape is permanently "locked in." After complete cooling, the mold can be opened, and the high-performance, dimensionally accurate, environmentally friendly, low-noise automotive rubber shock absorber can be removed.

[0015] Preferably, the mixing temperature in step S1 is 75-85℃.

[0016] Preferably, the heating temperature in step S2 is 130-150°C, and the cooling and shaping temperature in step S3 is below 80°C.

[0017] Preferably, the preparation of the furan-functionalized epoxidized natural rubber includes: epoxidizing the natural rubber and then reacting it with furfurylamine to graft furan groups.

[0018] Preferably, the preparation of the core-shell structured nanofiller includes: chemically grafting a polysiloxane shell layer onto the surface of a crystalline nanocellulose core.

[0019] Preferably, the process also includes a recycling step: crushing the production waste or scrap of the shock absorber and directly using the crushed material to repeat steps S2 and S3 to manufacture new shock absorbers.

[0020] This invention provides an environmentally friendly, low-noise automotive rubber shock absorber and its manufacturing process. It offers the following advantages: 1. This invention achieves a complete closed-loop recycling and reuse of high-performance rubber materials, fundamentally solving the black pollution problem caused by the disposal of traditional rubber products. Its beneficial effect lies in the fact that, through an innovative dynamic reversible network design, both scraps from the production process and end-of-life scrap parts can be easily physically crushed and reused as 100% raw materials in the manufacturing process to produce new products with no performance loss. This constitutes a truly cradle-to-cradle green circular system, possessing enormous environmental value and resource-saving significance.

[0021] 2. This invention significantly improves the vibration damping and noise reduction performance of materials, providing a novel technical solution for manufacturing high-performance, low-noise components. Its beneficial effect lies in the introduction of a specially designed core-shell structured nanofiller, which constructs an innovative interfacial friction energy dissipation mechanism within the material. This mechanism, in synergy with the viscoelastic internal friction of the rubber matrix itself, forms a dual energy dissipation pathway, thereby enabling more efficient absorption and conversion of vibration energy, exhibiting superior damping characteristics under a wide range of operating conditions.

[0022] 3. This invention revolutionizes the traditional rubber manufacturing process, greatly simplifying its production and significantly reducing energy consumption and production cycle. Its beneficial effect lies in the fact that, based on the dynamic thermal reversibility of materials, this invention completely replaces the time-consuming, energy-intensive, and chemically complex vulcanization steps in the traditional rubber industry with a simple physical process of "heating and melting - pressing and molding - cooling and solidifying." This not only improves production efficiency but also avoids potentially harmful byproducts generated during vulcanization, promoting the rubber manufacturing industry towards a more efficient, cleaner, and more economical direction.

[0023] 4. This invention endows the material with inherent self-healing capabilities, greatly improving the reliability and service life of the product. Its beneficial effect lies in the fact that the dynamically reversible chemical network allows the material to undergo structural self-healing after external damage, through gentle thermal stimulation that induces the breakage and recombination of chemical bonds at the damaged interface. This intelligent damage repair capability effectively prevents the accumulation and expansion of minor damage, avoids premature component failure, and ensures long-term stable operation in harsh environments.

[0024] 5. This invention integrates multiple excellent properties such as high damping performance, recyclability, and self-healing, breaking the inherent contradictions between traditional material properties. Its beneficial effect lies in the fact that, through the synergistic design of dynamic chemical networks and functional physical mechanisms, this invention no longer requires a trade-off between high performance and recyclability. The resulting composite material possesses both the high strength and high elasticity of traditional thermosetting rubbers and the reprocessing capability and intelligent response characteristics of thermoplastic materials, achieving a high degree of unity in multifunctionality and paving the way for the development of next-generation high-performance sustainable materials. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the process method of the present invention. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see the appendix Figure 1 This invention provides an environmentally friendly, low-noise automotive rubber shock absorber and its manufacturing process, comprising the following steps: Example 1: This embodiment describes the process of preparing a rubber damping component using preferred intermediate range parameters.

[0028] Preparation of F-ENR: Furan-functionalized epoxidized natural rubber (F-ENR) was prepared using the aforementioned method, with its epoxy content controlled to be approximately 25 mol.

[0029] Preparation of PSX-g-CNC: Core-shell structured nanofiller (PSX-g-CNC) was prepared using the method described above.

[0030] Mixing of dynamically reversible rubber composites: Equipment and temperature: A double-roll open rubber mixing mill is used, and the roller temperature is controlled at 80℃.

[0031] Formula (parts by weight): F-ENR: 100 copies; PSX-g-CNC: 15 servings; Bimaleimide (BMI): 5 parts; Antioxidant RD: 2 parts; Stearic acid: 1.5 parts; Process: After softening the F-ENR wrapping roller, add PSX-g-CNC and additives, and mix for 20 minutes. Then add BMI, continue mixing for 4 minutes, and then sheet and cool.

[0032] Thermoplastic molding of shock absorbers: Heating and melting: Place the premixed film in the mold, heat to 140°C and keep warm for 3 minutes.

[0033] Pressurization: Apply a pressure of 12 MPa.

[0034] Cooling and shaping: Maintain pressure and cool the mold to 75°C before demolding.

[0035] Example 2: This embodiment describes the process of preparing a rubber damping component using parameters close to the lower limit of the claims to verify the feasibility of the scheme at lower crosslinking degree and lower filler content.

[0036] Preparation of F-ENR: Using a method similar to that in Example 1, F-ENR with an epoxy group content of approximately 20 mol% was prepared by adjusting the reaction time.

[0037] Preparation of PSX-g-CNC: PSX-g-CNC was prepared using a method similar to that in Example 1.

[0038] Mixing of dynamically reversible rubber composites: Equipment and temperature: A double-roll open rubber mixing mill is used, and the roller temperature is controlled at 75℃.

[0039] Formula (parts by weight): F-ENR: 100 copies; PSX-g-CNC: 5 copies; Maleimide (BMI): 3 parts; Antioxidant RD: 2 parts; Stearic acid: 1.5 parts; Process: After softening the F-ENR wrapping roller, add PSX-g-CNC and additives, and mix for 18 minutes. Then add BMI, continue mixing for 3 minutes, and then sheet and cool.

[0040] Thermoplastic molding of shock absorbers: Heating and melting: Place the premixed film in the mold, heat to 130°C and keep warm for 4 minutes.

[0041] Pressurization: Apply a pressure of 10 MPa.

[0042] Cooling and shaping: Maintain pressure and cool the mold to 78°C before demolding.

[0043] Example 3: This embodiment describes the process of preparing a rubber damping component using parameters close to the upper limit of the claims to verify the feasibility of the scheme under high crosslinking degree and high filler content.

[0044] Preparation of F-ENR: Using a method similar to that in Example 1, F-ENR with an epoxy group content of approximately 30 mol% was prepared by adjusting the reaction time.

[0045] Preparation of PSX-g-CNC: PSX-g-CNC was prepared using a method similar to that in Example 1.

[0046] Mixing of dynamically reversible rubber composites: Equipment and temperature: A double-roll open rubber mixing mill is used, and the roller temperature is controlled at 85℃.

[0047] Formula (parts by weight): F-ENR: 100 copies; PSX-g-CNC: 20 servings; Maleimide (BMI): 8 parts; Antioxidant RD: 2 parts; Stearic acid: 1.5 parts; Process: After softening the F-ENR wrapping roller, add PSX-g-CNC and additives, and mix for 25 minutes. Then add BMI, continue mixing for 5 minutes, and then sheet and cool.

[0048] Thermoplastic molding of shock absorbers: Heating and melting: Place the premixed film in the mold, heat to 150°C and keep warm for 2 minutes.

[0049] Pressurization: Apply a pressure of 15 MPa.

[0050] Cooling and shaping: Maintain pressure and cool the mold to 70°C before demolding.

[0051] Comparative Example 1: Compared to Example 1, the difference lies in the use of a conventional, irreversible vulcanization crosslinking system. Specifically, 100 parts by weight of furan-functionalized epoxidized natural rubber (F-ENR) were replaced with 100 parts by weight of ordinary epoxidized natural rubber (ENR, epoxy content 25 mol%), and 5 parts by weight of bimaleimide (BMI) were replaced with a conventional vulcanization system consisting of 2 parts by weight of sulfur, 1.5 parts by weight of accelerator CZ, and 3 parts by weight of zinc oxide. The molding process was also changed accordingly to isothermal vulcanization at 160°C for 15 minutes, instead of thermoplastic molding. Everything else remained the same.

[0052] Comparative Example 2: Compared with Example 1, the difference is that a conventional nanofiller was used instead of the core-shell structured filler of the present invention. Specifically, 15 parts by weight of the core-shell structured nanofiller (PSX-g-CNC) were replaced with an equal weight of ordinary crystalline nanocellulose (CNC) without any surface treatment. The remaining components, proportions, and preparation processes were the same.

[0053] Comparative Example 3: Compared to Example 1, the difference lies in the absence of one of the key components in the dynamic reversible crosslinking system. Specifically, 5 parts by weight of bimaleimide (BMI) were not added during the mixing step, meaning only F-ENR was present without the crosslinking agent that reacts with it. The remaining components, proportions, and preparation process remained the same.

[0054] Comparative Example 4: Compared with Example 1, the difference lies in that the amount of core-shell structured nanofiller exceeds the upper limit claimed by this invention. Specifically, the amount of core-shell structured nanofiller (PSX-g-CNC) was increased from 15 parts by mass to 30 parts by mass. All other aspects remained the same.

[0055] Comparative Example 5: Compared with Example 1, the difference lies in the amount of dynamic crosslinking agent used, which is lower than the lower limit of protection claimed by this invention. Specifically, the amount of bimaleimide (BMI) was reduced from 5 parts by mass to 1 part by mass. All other aspects remained the same.

[0056] Comparative Example 6: Compared to Example 1, the difference lies in omitting a core innovative step in the manufacturing process. Specifically, in the thermoplastic compression molding step, the step of heating the mold to 140°C to melt the material is omitted; instead, a pressure of 12 MPa is directly applied to the rubber compound at the mixing temperature (80°C) for molding. All other steps remain the same.

[0057] Test Example 1: Recyclability and Process Feasibility Test Experimental description: This test case aims to visually verify the closed-loop recyclability of the material described in this invention through comparative experiments, and to demonstrate the necessity and superiority of its associated thermoplastic molding process. The experiment consists of two parts: Part A - Recyclability Test: Comparing the sample of the present invention (Example 1) with a conventional vulcanized rubber sample (Comparative Example 1) to see if they can be reprocessed and molded after being crushed.

[0058] Part B - Process Feasibility Test: The molding quality of samples prepared using the correct process of the present invention (Example 1) and the incorrect process (Comparative Example 6) is compared to demonstrate the key role of the "high-temperature melting" step in the process of the present invention.

[0059] Experimental steps: Part A: Recyclability Testing Raw material preparation: Take the scrap material or a complete sample produced after the first molding of "Example 1" and mark it as R-E1.

[0060] Take the scrap material or a complete sample produced after the first vulcanization molding of "Comparative Example 1" and mark it as R-C1.

[0061] Physical crushing: Samples R-E1 and R-C1 were placed in the same shear crusher and crushed into granular recycled material with an average particle size of 2-5 mm.

[0062] Secondary molding attempt: For R-E1 recycled material: it was placed completely into the same mold as in Example 1, and the molding process of Example 1 was strictly followed, namely: heating to 140°C and holding for 3 minutes, applying a pressure of 12MPa, and then cooling to 75°C before demolding.

[0063] For R-C1 recycled material: place it completely into the same mold as Comparative Example 1, and strictly follow the vulcanization process of Comparative Example 1, that is: demold after holding at a constant temperature and pressure at 160℃ for 15 minutes.

[0064] Results Evaluation: The product after secondary molding is evaluated. This is mainly done by visually observing its surface morphology and structural integrity, and by manually bending or pressing it to qualitatively determine whether it possesses basic mechanical strength and structural cohesion.

[0065] Part B: Process Feasibility Test Sample acquisition: The final molded samples of “Example 1” and “Comparative Example 6” prepared according to their respective methods were taken directly.

[0066] Macroscopic morphological assessment: Under natural light, visually inspect and record the surface finish, color uniformity, and presence of obvious defects such as bubbles, flow marks, and unfused areas on both samples.

[0067] Inspect the edges, corners, and thin-walled areas of the sample to assess the integrity of the mold filling.

[0068] Preliminary characterization of physical properties: Using a Shore A hardness tester, hardness measurements were taken at five different locations on the surface of each sample. The values ​​were recorded and the average and standard deviation were calculated to assess the compactness and uniformity of the material molding.

[0069] Table 3.1 Comparison of test results for recyclability and process feasibility

[0070] The results of Test Example 1 clearly reveal the fundamental innovations of this invention in material recyclability and manufacturing process. The sample in Example 1, after physical pulverization, can be reheated, melted, and reshaped into a structurally complete product, directly stemming from its unique dynamic reversible covalent network. The mechanism lies in the fact that when the temperature rises above the dissociation temperature (140°C in this example), the Diels-Alder bonds constituting the three-dimensional network undergo reversible breakage, causing the cross-linked solid rubber to transform into a fluid molten state, thereby achieving material remelting and shaping. When the temperature decreases, these chemical bonds spontaneously reform, restoring the material to its original high-performance solid structure. This is the chemical basis for the true physical closed-loop recycling achieved by this invention.

[0071] In stark contrast, Comparative Example 1, which uses a traditional vulcanization system, completely lacks this capability. The sulfur-sulfur cross-links formed within it are permanent and thermally irreversible. Once formed, heating cannot break or melt them; it only leads to thermal degradation of the material at higher temperatures. Therefore, even after the waste is crushed, reheating and pressurizing it will only maintain a loose particle shape and cannot reform into a cohesive and usable whole. This comparison powerfully demonstrates that this invention, by constructing a dynamic reversible network, fundamentally overcomes the technical bottleneck of the inability to recycle and reuse traditional high-performance rubber.

[0072] Furthermore, the comparison between Example 1 and Comparative Example 6 highlights the necessity of the "thermoplastic" molding process proposed in this invention. The success of Example 1 stemmed from molding at a temperature above the network dissociation temperature, where the material was in a low-viscosity molten state, perfectly filling the mold. In contrast, Comparative Example 6 was molded below the network dissociation temperature, leaving the material in a highly elastic solid state with extremely poor flowability. This prevented effective mold filling, resulting in severe molding defects in the product. This clearly demonstrates that the innovative material system of this invention must be matched with the innovative manufacturing process proposed in this invention; that is, precise temperature control is needed to guide the reversible conversion between the solid and fluid states of the material in order to ultimately achieve the fabrication of high-performance, high-quality shock-absorbing components.

[0073] Test Example 2: Comparative Test of Vibration Damping and Noise Reduction Performance (Dynamic Mechanical Properties) Experimental description: This test case aims to quantify and compare the differences in damping performance between the sample of this invention (Example 1) and the sample using conventional filler (Comparative Example 2) through dynamic mechanical analysis (DMA). The core evaluation index is the loss factor (…). This value directly reflects the efficiency with which the material converts mechanical vibration energy into thermal energy. This comparison verifies the contribution of the core-shell structured nanofiller designed in this invention to introducing a new mechanism of "interfacial friction energy dissipation," thereby improving the overall damping performance of the material.

[0074] Experimental steps: Sample preparation: Strip-shaped samples with dimensions of 25mm × 6mm were cut from the premixed film (or the flat part of the final product) with a thickness of approximately 2.5mm prepared according to the methods of Example 1 and Comparative Example 2.

[0075] Ensure the sample surface is flat and free of nicks or cracks. Take 3 valid samples from each sample group for testing, and take the average value of the results.

[0076] Instruments and testing conditions: Instrument: Dynamic mechanical analyzer (DMA), such as TA Instruments Q800 or equivalent.

[0077] Test mode: Tensile Mode.

[0078] Test procedure: Perform a temperature scan test.

[0079] Static preload: 0.02N; Strain amplitude: 0.1% (ensure the test is within the linear viscoelastic region of the material); Test frequency: 10Hz (simulating medium frequency vibration conditions); Temperature range: -40℃ to 80℃; Heating rate: 3℃ / min; Data acquisition and processing: Throughout the temperature scan, the storage modulus (E'), loss modulus (E''), and loss factor (E'') of the sample were continuously recorded. =E'' / E') changes with temperature.

[0080] The focus was on extracting and comparing the loss factor values ​​of two samples in common temperature ranges during actual automotive operation (such as 0℃, 20℃, 40℃, 60℃, etc.).

[0081] Table 3.2 Dynamic Mechanical Properties (Loss Factor) Test results comparison (test frequency: 10Hz)

[0082] The above dynamic mechanical analysis results clearly demonstrate the significant advantages of this invention in vibration reduction and noise reduction performance. Data shows that, across the entire test temperature range, the loss factor of the sample in Example 1 (…) The loss factor was consistently higher than that of the sample in Comparative Example 2. The loss factor is a direct indicator of the damping performance of a material; a higher value means that the material has a stronger ability to absorb and dissipate vibrational energy. This leap in performance is not due to the rubber matrix itself, but directly to the core-shell structured nanofiller unique to this invention.

[0083] The core mechanism of this invention lies in its innovative construction of a novel physical energy dissipation mechanism by coating a rigid crystalline nanocellulose core with a flexible polysiloxane shell. When the damping component is subjected to external vibration, a microscopic, instantaneous relative motion occurs between the highly rigid core and the relatively soft rubber matrix. This specially designed shell, acting like a nanoscale "sliding bearing," allows and facilitates this controlled interfacial micro-slip. It is precisely in this high-frequency, repetitive interfacial friction process that a large amount of vibrational mechanical energy is efficiently converted into heat energy and dissipated, thereby achieving a superior damping effect.

[0084] In contrast, the traditional, untreated nanofiller used in Comparative Example 2 primarily functions to achieve mechanical reinforcement through strong interfacial bonding with the rubber matrix, but it lacks the aforementioned interfacial friction energy dissipation mechanism. Therefore, its overall damping performance mainly relies on the viscoelastic internal friction generated by the movement of the rubber molecular chain segments themselves. The energy dissipation pathway is singular and inefficient, resulting in a significantly lower loss factor than in Example 1. This comparative result strongly demonstrates that the present invention, by introducing the innovative mechanism of "interfacial friction energy dissipation," successfully constructs a dual energy dissipation system within the material.

[0085] Test Example 3: Basic Mechanical Properties and Rationality Test of Component Range Experimental description: This test case aims to verify the integrity, synergy, and rationality of the proposed key component content range of the composite material formulation system of this invention through a series of standard rubber physical property tests. The experiment will compare the differences in basic mechanical properties between the baseline sample (Example 1), the sample lacking the key component (Comparative Example 3), and the sample with the key component content exceeding the recommended range (Comparative Examples 4 and 5), thereby demonstrating the scientific nature and necessity of the formulation design of this invention.

[0086] Experimental steps: Sample preparation: The premixed films of Example 1, Comparative Example 3, Comparative Example 4 and Comparative Example 5 were placed in a flatbed molding machine and pressed into flat samples with a thickness of 2.0±0.2mm under their respective molding conditions for subsequent testing.

[0087] After the sample has been left to stand at standard room temperature for at least 16 hours, the sample is cut into specimens using a dumbbell-shaped cutter conforming to GB / T528 standard for tensile property testing.

[0088] For hardness and compression set tests, cylindrical or sheet specimens of the required size are molded.

[0089] Tensile property test: According to the standard GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0090] Equipment: Electronic universal testing machine.

[0091] Procedure: Clamp the dumbbell-shaped specimen on the testing machine and stretch it at a tensile rate of 500 mm / min until the specimen breaks. Record its tensile strength (stress at fracture) and elongation at break. Test 5 valid specimens for each group of samples, and take the median result.

[0092] Hardness test: According to the standard GB / T531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test (Shore hardness)".

[0093] Equipment: Shore A hardness tester.

[0094] Procedure: Place a flat sample (if the thickness is less than 6 mm, multiple samples can be stacked) on a hard platform. Press the indenter of the hardness tester vertically onto the sample surface and quickly read the value. Select 5 different measuring points at least 6 mm apart on each sample for measurement, and take the arithmetic mean of the results.

[0095] Compression permanent deformation test: According to the standard GB / T7759.1-2015 "Determination of compression set of vulcanized or thermoplastic rubber - Part 1: Under normal and high temperature conditions".

[0096] Equipment: Compression set tester, constant temperature oven.

[0097] Procedure: Measure the initial height of the cylindrical specimen, then place it in a testing apparatus and compress it by 25%. Place the testing apparatus containing the specimen in an oven at 100°C and maintain this temperature for 22 hours. After removal, remove the specimen from the apparatus and allow it to recover at room temperature for 30 minutes before measuring its final height. Calculate the compression set using the formula.

[0098] Table 3.3 Results of Basic Mechanical Properties and Rationality Tests on Component Range

[0099] The above-mentioned basic mechanical property test results fundamentally verify the integrity and scientific validity of the formulation system of this invention. The significant performance difference between Example 1 and Comparative Example 3 directly reveals the core role of the dynamic reversible crosslinking network in this invention. In Comparative Example 3, due to the lack of the key bimaleimide component, the furan-functionalized rubber macromolecular chains cannot form effective chemical bonds through the Diels-Alder reaction. Therefore, the material is essentially an uncrosslinked system composed of fillers and polymers physically mixed, unable to form a cohesive three-dimensional network capable of withstanding loads and achieving elastic recovery, ultimately exhibiting extremely low tensile strength, hardness, and almost complete loss of elastic recovery ability (compression set approaching 100%).

[0100] Meanwhile, by comparing the data from Example 1 with those from Comparative Examples 4 and 5, the necessity of synergistic effects of each component within a specific content range can be clearly seen. When the crosslinking agent content is too low (Comparative Example 5), the density of the formed crosslinking network is insufficient, the molecular chains between network nodes are too long and the constraint force is weak, resulting in a sharp decrease in the material's ability to resist permanent deformation, manifested as a significantly increased compression set value. Conversely, when the content of functional filler is too high (Comparative Example 4), excessive rigid filler will severely restrict the chain segment movement of the rubber matrix and may generate stress concentration points due to uneven dispersion, leading to a significant decrease in the material's toughness (elongation at break), exhibiting a brittle tendency, and also impairing its elastic recovery ability at high temperatures.

[0101] In summary, the superior overall performance of this invention does not stem from a simple accumulation of components, but rather from a carefully designed synergistic system. Only when the density of the dynamic reversible crosslinking network (determined by the crosslinking agent content) and the reinforcing and damping effects of the functional fillers (determined by the filler content) are within an optimized balance range can the material simultaneously exhibit sufficient structural strength, high elasticity, and high reliability. This series of comparative data strongly demonstrates that the component ratio range proposed in this invention is a necessary condition for achieving this key synergistic effect and thus obtaining high-performance recyclable rubber composite materials.

[0102] Test Example 4: Self-Healing Capability Verification Test Experimental description: This test case aims to visually verify the self-healing capability of the material of this invention due to its dynamic reversible network, and to compare it with conventional vulcanized rubber that does not possess this property. The experiment involved applying macroscopic damage (complete transection) to the sample, followed by mild thermal stimulation, and then evaluating the degree of recovery of its structural integrity and mechanical properties. This directly demonstrates the potential value of this invention in extending material lifespan and improving reliability.

[0103] Experimental steps: Sample preparation and damage application: Long strip-shaped standard samples with dimensions of 50mm × 10mm × 2mm were cut from the samples prepared according to the methods of Example 1 and Comparative Example 1, respectively.

[0104] Using a clean, sharp blade, completely cut each sample at its midpoint, creating two separate cross-sections.

[0105] Repair process: For the sample of Example 1: Carefully realign and tightly bond the two newly generated cross-sections. Place the bonded sample on a flat polytetrafluoroethylene film and transfer it into a constant temperature oven preheated to 100°C for heat treatment for 60 minutes.

[0106] For the sample of Comparative Example 1: the same operation as in Example 1 was performed, that is, after the two cut surfaces were joined together, the same heat treatment was carried out in an oven at 100°C as a negative control.

[0107] For all samples: After heat treatment, remove the samples and allow them to cool naturally at room temperature for at least 2 hours to stabilize their structure.

[0108] Repair effectiveness assessment: Qualitative assessment: First, visually observe the healing status of the repair interface. Then, gently bend and stretch the repaired specimen by hand to qualitatively determine its bonding strength.

[0109] Quantitative assessment (restoration efficiency determination): a. Take a set of undamaged original specimens (Example 1 and Comparative Example 1), and test their original tensile strength according to GB / T 528 standard, denoted as . .

[0110] b. Perform a tensile test on the repaired specimen as well, and determine its tensile strength at the repair interface, denoted as . .

[0111] c. Calculate the repair efficiency according to the formula. .

[0112] Table 3.4 Comparison of Self-Healing Performance Test Results

[0113] The results of the self-healing ability test described above intuitively and powerfully demonstrate the inherent intelligent properties of the material system of this invention. The sample in Example 1, after being completely severed, regained its structural integrity and achieved up to 83% of its original tensile strength through only mild heat treatment. The fundamental mechanism of this phenomenon lies in the dynamic reversible covalent network constructed within it. When heat (100°C in this example) is applied to the damaged interface, the Diels-Alder addition bonds at the fracture surface undergo reversible dissociation, allowing the ends of the severed rubber macromolecular chains to regain local mobility. When the two fracture surfaces are reattached, these "activated" molecular chains can diffuse across the interface, re-entangle, and undergo another Diels-Alder reaction during subsequent cooling to form new covalent bonds, thus "stitching" the damage and repairing the macroscopic structure.

[0114] In stark contrast, the Comparative Example 1 sample, employing a conventional permanent cross-linked network, showed absolutely no signs of healing after undergoing the same damage and heat treatment. This is because the internal sulfur-sulfur cross-links are thermally irreversible; once broken during cutting, they cannot be reconnected by heating. The applied heat is insufficient to break these stable chemical bonds, and naturally, it cannot endow the molecular chains with the ability to re-move and recombine. Therefore, the damage is permanent, and the material's repair efficiency is zero. This contrast clearly distinguishes the dynamic characteristics of the present invention from the static characteristics of conventional materials.

[0115] The test results not only demonstrate a performance indicator but also profoundly confirm the core innovative concept of this invention. They prove the dynamic and reversible chemical mechanism that endows the material with recyclability, and also endow it with the potential for damage repair during service. This "self-healing" capability means that components made from the material of this invention, after suffering damage such as microcracks or scratches, can potentially have their service life extended and their operational reliability improved through simple heat treatment. This provides a novel and highly valuable technical path for solving the problem of premature failure of high-performance elastomer materials under harsh operating conditions.

[0116] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly, low-noise automotive rubber shock absorber, characterized in that, The shock absorber is made of a rubber composite material, which comprises the following components: Dynamically reversibly crosslinked rubber matrix; Core-shell structured nanofillers; The dynamically reversibly crosslinked rubber matrix comprises: Furan-functionalized epoxidized natural rubber: 100 parts by weight; Bimaleimide: 3-8 parts by weight; The content of the core-shell structured nanofiller is 5-20 parts by mass.

2. The environmentally friendly, low-noise automotive rubber shock absorber according to claim 1, characterized in that, The furan-functionalized epoxidized natural rubber is prepared by epoxidation and furan group grafting reaction of natural rubber.

3. The environmentally friendly, low-noise automotive rubber shock absorber according to claim 1, characterized in that, The core-shell structured nanofiller comprises: A core composed of crystalline nanocellulose; A shell layer made of polysiloxane covering the surface of the core.

4. The environmentally friendly, low-noise automotive rubber shock absorber according to claim 3, characterized in that, The polysiloxane shell and the crystalline nanocellulose core are connected by chemical bonds.

5. A manufacturing process for producing the environmentally friendly, low-noise automotive rubber shock absorber as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Mixing: Furan-functionalized epoxidized natural rubber, core-shell structured nanofillers, and bimaleimide are mixed under conditions below the dissociation temperature of the dynamic reversible crosslinking system to obtain a premix; S2: Molding: The premix is ​​placed in a mold, heated and pressurized under conditions higher than the dissociation temperature of the dynamic reversible crosslinking system, so that the premix melts and fills the mold; S3: Shaping: Cool the mold to a temperature below the dissociation temperature of the dynamic reversible crosslinking system, so that the premix is ​​solidified and shaped in the mold.

6. The manufacturing process of an environmentally friendly, low-noise automotive rubber shock absorber according to claim 5, characterized in that, The mixing temperature in step S1 is 75-85℃.

7. The manufacturing process of an environmentally friendly, low-noise automotive rubber shock absorber according to claim 5, characterized in that, The heating temperature in step S2 is 130-150℃, and the cooling and shaping temperature in step S3 is below 80℃.

8. The manufacturing process of an environmentally friendly, low-noise automotive rubber shock absorber according to claim 5, characterized in that, The preparation of the furan-functionalized epoxidized natural rubber includes: epoxidizing the natural rubber and then reacting it with furfurylamine to graft furan groups.

9. The manufacturing process of an environmentally friendly, low-noise automotive rubber shock absorber according to claim 5, characterized in that, The preparation of the core-shell structured nanofiller includes: chemically grafting a polysiloxane shell layer onto the surface of a crystalline nanocellulose core.

10. The manufacturing process of an environmentally friendly, low-noise automotive rubber shock absorber according to claim 5, characterized in that, It also includes a recycling step: crushing the production waste or scrap of the shock absorber and directly using the crushed material to repeat steps S2 and S3 to manufacture new shock absorbers.

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