Glass fiber reinforced rubber composite material and preparation method thereof

Abstract

The invention discloses a glass fiber reinforced rubber composite material and a preparation method thereof. The preparation method comprises the following steps: modifying the glass fiber by using an amino-epoxy silane compound coupling agent solution, and then stirring the modified glass fiber with part of the rubber matrix, the liquid interface compatilizer and silane-treated boron nitride in a closed container at a high speed to prepare uniform mixed slurry; and mixing the residual rubber matrix, the vulcanization system and the reinforcing filler, adding the mixed slurry, and carrying out mold pressing vulcanization to obtain the composite material. The compound coupling agent and the liquid interface compatilizer cooperatively construct a tough interface, a step-by-step process of prefabricated mixed slurry is combined, efficient dispersion and structural protection of the fibers and the functional filler are achieved, and the obtained composite material has excellent tensile strength and tearing strength, low dynamic heat generation and high thermal conductivity; the technical problems that traditional glass fiber reinforced rubber is weak in interface bonding, uneven in dispersion and single in function are solved.

Description

Technical Field

[0001] This invention relates to the field of polymer material processing technology, and in particular to a glass fiber reinforced rubber composite material and its preparation method. Background Technology

[0002] In the rubber industry, fiber reinforcement technology is often used to improve the mechanical properties of rubber products. Glass fiber, due to its high strength, high modulus, and low cost, has become one of the commonly used reinforcing materials. However, glass fiber has a smooth surface and is chemically inert, resulting in weak interfacial bonding with the rubber matrix. Under stress, it is prone to interfacial delamination, leading to low reinforcement efficiency. Simultaneously, glass fiber is difficult to disperse uniformly in a hydrophobic rubber matrix, easily agglomerating to form stress concentration points, which not only reduces material properties but may also impair its dynamic fatigue life and durability. Traditional improvement methods often focus on treating glass fiber with a single silane coupling agent or directly dispersing it through high-shear mixing processes. However, these methods often fail to achieve a synergistic effect of microscopic uniform dispersion and strong interfacial bonding while maintaining the fiber aspect ratio. Furthermore, existing glass fiber reinforced rubber composites have limited functionality, failing to meet the demands of high-end applications for integrated multifunctional materials such as thermal conductivity and vibration damping. Therefore, developing a novel preparation method that can achieve efficient dispersion of glass fiber in a rubber matrix, form a strong and tough interface, and impart specific functions to the composite material has become an urgent technical problem to be solved in this field. Summary of the Invention

[0003] To address the above problems, this invention proposes a glass fiber reinforced rubber composite material and its preparation method. First, surface-modified glass fibers are mixed with a portion of the rubber matrix, a liquid interface compatibilizer, and functional additives to form a uniform slurry, which is then mixed with the remaining rubber matrix and vulcanized.

[0004] This invention can be achieved through the following technical solutions: A method for preparing a glass fiber reinforced rubber composite material includes the following steps: Step 1: Immerse the glass fiber in a composite coupling agent solution, remove it and dry it to obtain surface-modified glass fiber; Step 2: Surface-modified glass fibers, a portion of the rubber matrix, liquid interface compatibilizer, and functional additives are mixed at high speed in a sealed container at 60-90°C to prepare a uniformly dispersed fiber slurry; wherein the portion of the rubber matrix accounts for 20%-40% of the total mass of the rubber matrix; Step 3: Add the remaining rubber matrix, vulcanization system compounding agent and reinforcing filler into the internal mixer and mix at 80-120℃ and rotor speed of 30-80rpm for 2-5 minutes. Then add the mixed slurry obtained in step 2 and continue mixing for 3-8 minutes. Discharge the rubber to obtain the compound. Step 4: Place the rubber compound in a mold and perform compression molding and vulcanization at a temperature of 150-180℃ and a pressure of 10-20MPa. The vulcanization time is the positive vulcanization time T90 of the rubber compound to obtain a glass fiber reinforced rubber composite material.

[0005] Preferably, the glass fiber in step 1 is chopped glass fiber with a length of 3-15 mm and a diameter of 10-20 μm, and its addition amount is 10%-50% of the total mass of the rubber matrix.

[0006] Preferably, the complex coupling agent solution in step 1 comprises an aminosilane coupling agent and an epoxysilane coupling agent, with a mass ratio of 1:(0.5-2).

[0007] Preferably, the liquid interface compatibilizer in step 2 is a carboxyl-terminated liquid nitrile rubber or an epoxy-terminated liquid nitrile rubber, and its addition amount is 1%-5% of the total mass of the rubber matrix.

[0008] Preferably, the functional additive in step 2 is boron nitride surface-treated with a silane coupling agent, with a flake diameter of 5-30 μm, and the amount added is 2%-8% of the total mass of the rubber matrix.

[0009] Preferably, in step 2, the high-speed stirring speed is 800-2000 rpm and the mixing time is 10-30 min.

[0010] Preferably, in step 3, the compounding agent of the vulcanization system accounts for 3%-15% of the total mass of the rubber matrix; and the reinforcing filler accounts for 20%-80% of the total mass of the rubber matrix.

[0011] Preferably, after adding the mixed slurry in step 3, the rotor speed of the internal mixer is reduced to 50%-70% of the original speed.

[0012] Preferably, in step 4, a constant magnetic field with an intensity of 0.1-0.5T perpendicular to the molding direction is applied in the early stage of molding vulcanization, and the duration is 33%-50% of the total vulcanization time.

[0013] The beneficial effects of this invention are: This invention constructs a chemically coupled interface layer on the surface of glass fibers by compounding aminosilane and epoxysilane, achieving both high strength and moderate flexibility. The active functional groups at the ends of this layer can form stable chemical bonds with the rubber matrix, fundamentally overcoming the weakness of the interface bonding in traditional single coupling agents. The introduction of liquid interface compatibilizers such as carboxyl-terminated liquid nitrile rubber not only further enhances the chemical affinity of the interface but also forms a flexible buffer phase with excellent energy dissipation capacity between the rigid fiber and the flexible rubber, significantly improving the dynamic fatigue performance and tear resistance of the material. Furthermore, this invention pre-mixes the surface-modified glass fibers, liquid interface compatibilizer, boron nitride functional additive, and a portion of the rubber matrix under mild shear conditions, achieving microscopic uniform dispersion and effective encapsulation of the reinforcing fibers and functional fillers. This maximizes the protection of the fiber aspect ratio during subsequent mixing, avoiding fiber breakage and filler agglomeration caused by traditional high-strength one-step mixing. The synergistic effect of these three technologies ultimately results in a composite material that not only possesses excellent static mechanical properties (high tensile strength and high tensile stress), but also exhibits significant comprehensive advantages in dynamic compression heat generation, tear resistance, and thermal conductivity, achieving a perfect combination of high strength, high durability, and integrated functionality. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 The static mechanical properties of rubber composite materials; Figure 2 The tear strength of the rubber composite material; Figure 3 The results are from dynamic compression heat generation tests on rubber composite materials. Figure 4 is the thermal conductivity of the rubber composite material. Detailed Implementation

[0015] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0016] Example 1: A method for preparing a glass fiber reinforced rubber composite material, comprising the following steps: Step 1: Add 10.0g of boron nitride powder (5μm in diameter) to 100mL of anhydrous ethanol and ultrasonically disperse for 30min to form a suspension; separately add 0.3g of silane coupling agent (KH550) to 100mL of ethanol-water mixed solvent (pH 4.0) for hydrolysis for 45min; then add the hydrolysate dropwise to the suspension and reflux at 80℃ for 6h; after the reaction is completed, filter, wash with ethanol and deionized water, vacuum dry at 90℃ for 12h, and grind through a 200-mesh sieve to obtain surface-modified boron nitride; Step 2: Dissolve γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in 95% ethanol solution at a mass ratio of 1:0.5 to prepare a complex coupling agent solution. Step 3: The components and amounts of the compounding agents in the vulcanization system are as follows: sulfur 2.0 phr, N-cyclohexyl-2-benzothiazole sulfenamide 1.0 phr, diphenylguanidine 0.2 phr, zinc oxide 4.0 phr, stearic acid 1.5 phr, N-isopropyl-N'-phenyl-p-phenylenediamine 1.5 phr; Step 4: Immerse 10g of short glass fibers (10μm in diameter and 3mm in length) in a complex coupling agent solution, remove and dry to obtain surface-modified glass fibers; Step 5: Mix the surface-modified glass fiber, 20g of natural rubber, 1g of carboxyl-terminated liquid nitrile rubber and 2g of functional additives in a sealed container at 60°C and 800rpm for 30min to prepare a mixed slurry with uniform fiber dispersion. Step 6: Add the remaining 80g of natural rubber, 3g of vulcanization system compounding agent, and 20g of N330 carbon black into a mixer and mix for 5 minutes at 80℃ and a rotor speed of 30rpm. Then add the mixed slurry prepared in step 5, reduce the rotor speed of the mixer to 50g of the original speed, and continue mixing for 3 minutes. Discharge the rubber to obtain the compound. Take an appropriate amount of the compound and use a rotorless vulcanizing apparatus to determine its vulcanization curve according to ASTM D5289 standard under test conditions of 160℃, 1.67Hz, and ±0.5° arc. The positive vulcanization time T90 is found to be 10 minutes. Step 7: Place the rubber compound in a mold, apply a constant magnetic field with an intensity of 0.1T perpendicular to the molding direction (for 5 minutes), and perform compression molding and vulcanization at a temperature of 150°C and a pressure of 10MPa to obtain a glass fiber reinforced rubber composite material.

[0017] Example 2: A method for preparing a glass fiber reinforced rubber composite material, comprising the following steps: Step 1: Add 10.0g of boron nitride powder (17.5μm in diameter) to 100mL of anhydrous ethanol and ultrasonically disperse for 30min to form a suspension; separately add 0.3g of silane coupling agent (KH550) to 100mL of ethanol-water mixed solvent (pH 4.0) for hydrolysis for 45min; then add the hydrolysate dropwise to the suspension and reflux at 80℃ for 6h; after the reaction is completed, filter, wash with ethanol and deionized water, vacuum dry at 90℃ for 12h, and grind through a 200-mesh sieve to obtain surface-modified boron nitride; Step 2: Dissolve γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in 95% ethanol solution at a mass ratio of 1:1.25 to prepare a complex coupling agent solution; Step 3: The components and dosage of the compounding agents in the vulcanization system are the same as in Example 1; Step 4: Immerse 30g of chopped glass fibers (15μm in diameter and 9mm in length) in a complex coupling agent solution, remove and dry to obtain surface-modified glass fibers; Step 5: Mix the surface-modified glass fiber, 30g of natural rubber, 3g of epoxy-terminated liquid nitrile rubber and 5g of functional additives in a sealed container at 75°C and 1400rpm for 20min to prepare a mixed slurry with uniform fiber dispersion. Step 6: Add the remaining 70g of natural rubber, 9g of vulcanization system compounding agent, and 50g of N330 carbon black into a mixer and mix at 100℃ and a rotor speed of 55rpm for 3.5min. Then add the mixed slurry prepared in Step 5, reduce the rotor speed of the mixer to 60g of the original speed, and continue mixing for 5.5min. Discharge the rubber to obtain the compound. Take an appropriate amount of the compound and use a rotorless vulcanizer to determine its vulcanization curve according to ASTM D5289 standard under test conditions of 160℃, 1.67Hz, and ±0.5° arc. The positive vulcanization time T90 is found to be 10min. Step 7: Place the rubber compound in a mold and apply a constant magnetic field with an intensity of 0.3T perpendicular to the molding direction (for 4.15 minutes). Perform molding vulcanization at a temperature of 165℃ and a pressure of 15MPa to obtain a glass fiber reinforced rubber composite material.

[0018] Example 3: A method for preparing a glass fiber reinforced rubber composite material, comprising the following steps: Step 1: Add 10.0g of boron nitride powder (30μm in diameter) to 100mL of anhydrous ethanol and ultrasonically disperse for 30min to form a suspension; separately add 0.3g of silane coupling agent (KH550) to 100mL of ethanol-water mixed solvent (pH 4.0) for hydrolysis for 45min; then add the hydrolysate dropwise to the suspension and reflux at 80℃ for 6h; after the reaction is completed, filter, wash with ethanol and deionized water, vacuum dry at 90℃ for 12h, and grind through a 200-mesh sieve to obtain surface-modified boron nitride; Step 2: Dissolve γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in 95% ethanol solution at a mass ratio of 1:2 to prepare a complex coupling agent solution. Step 3: The components and dosage of the compounding agents in the vulcanization system are the same as in Example 1; Step 4: Immerse 50g of chopped glass fibers (20μm in diameter and 15mm in length) in a complex coupling agent solution, remove and dry to obtain surface-modified glass fibers; Step 5: Mix the surface-modified glass fiber, 40g of natural rubber, 5g of carboxyl-terminated liquid nitrile rubber and 8g of functional additives in a sealed container at 90°C and 2000rpm for 10min to prepare a mixed slurry with uniform fiber dispersion. Step 6: Add the remaining 60g of natural rubber, 15g of vulcanization system compounding agent, and 80g of N330 carbon black into a mixer. Mix at 120℃ and a rotor speed of 80rpm for 2 minutes. Then add the mixed slurry prepared in Step 5. Reduce the rotor speed of the mixer to 70g of the original speed and continue mixing for 8 minutes. Discharge the rubber to obtain the compound. Take an appropriate amount of the compound and use a rotorless vulcanizing apparatus to determine its vulcanization curve according to ASTM D5289 standard under test conditions of 160℃, 1.67Hz, and ±0.5° arc. The positive vulcanization time T90 is found to be 10 minutes. Step 7: Place the rubber compound in a mold, apply a constant magnetic field with an intensity of 0.5T perpendicular to the molding direction (lasting for 3.3 minutes), and perform compression molding and vulcanization at a temperature of 180℃ and a pressure of 20MPa to obtain a glass fiber reinforced rubber composite material.

[0019] Comparative Example 1: The difference between this comparative example and Example 1 is that a single silane coupling agent (γ-aminopropyltriethoxysilane) is used instead of a complex coupling agent.

[0020] A method for preparing a glass fiber reinforced rubber composite material includes the following steps: Step 1: Add 10.0g of boron nitride powder (5μm in diameter) to 100mL of anhydrous ethanol and ultrasonically disperse for 30min to form a suspension; separately add 0.3g of silane coupling agent (KH550) to 100mL of ethanol-water mixed solvent (pH 4.0) for hydrolysis for 45min; then add the hydrolysate dropwise to the suspension and reflux at 80℃ for 6h; after the reaction is completed, filter, wash with ethanol and deionized water, vacuum dry at 90℃ for 12h, and grind through a 200-mesh sieve to obtain surface-modified boron nitride; Step 2: The components and dosage of the compounding agents in the vulcanization system are the same as in Example 1; Step 3: Impregnate 10g of chopped glass fibers (10μm in diameter and 3mm in length) in γ-aminopropyltriethoxysilane, remove and dry to obtain surface-modified glass fibers; Step 4: Mix the surface-modified glass fiber, 20g of natural rubber, 1g of carboxyl-terminated liquid nitrile rubber and 2g of functional additives in a sealed container at 60°C and 800rpm for 30min to prepare a uniformly dispersed fiber slurry. Step 5: Add the remaining 80g of natural rubber, 3g of vulcanization system compounding agent, and 20g of N330 carbon black into a mixer and mix for 5 minutes at 80℃ and a rotor speed of 30rpm. Then add the mixed slurry prepared in Step 4, reduce the rotor speed of the mixer to 50g of the original speed, and continue mixing for 3 minutes. Discharge the rubber to obtain the compound. Take an appropriate amount of the compound and use a rotorless vulcanizer to determine its vulcanization curve according to ASTM D5289 standard under test conditions of 160℃, 1.67Hz, and ±0.5° arc. The positive vulcanization time T90 is found to be 10 minutes. Step 6: Place the rubber compound in a mold, apply a constant magnetic field with an intensity of 0.1T perpendicular to the molding direction (for 5 minutes), and perform compression molding and vulcanization at a temperature of 150°C and a pressure of 10MPa to obtain a glass fiber reinforced rubber composite material.

[0021] Comparative Example 2: The difference between this comparative example and Example 1 is that no liquid interface compatibilizer is added.

[0022] A method for preparing a glass fiber reinforced rubber composite material includes the following steps: Step 1: Add 10.0g of boron nitride powder (5μm in diameter) to 100mL of anhydrous ethanol and ultrasonically disperse for 30min to form a suspension; separately add 0.3g of silane coupling agent (KH550) to 100mL of ethanol-water mixed solvent (pH 4.0) for hydrolysis for 45min; then add the hydrolysate dropwise to the suspension and reflux at 80℃ for 6h; after the reaction is completed, filter, wash with ethanol and deionized water, vacuum dry at 90℃ for 12h, and grind through a 200-mesh sieve to obtain surface-modified boron nitride; Step 2: Dissolve γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in 95% ethanol solution at a mass ratio of 1:0.5 to prepare a complex coupling agent solution. Step 3: The components and dosage of the compounding agents in the vulcanization system are the same as in Example 1; Step 4: Immerse 10g of short glass fibers (10μm in diameter and 3mm in length) in a complex coupling agent solution, remove and dry to obtain surface-modified glass fibers; Step 5: Mix the surface-modified glass fiber, 20g of natural rubber and 2g of functional additives in a sealed container at 60°C and 800rpm for 30 minutes to prepare a mixed slurry with uniform fiber dispersion. Step 6: Add the remaining 80g of natural rubber, 3g of vulcanization system compounding agent, and 20g of N330 carbon black into a mixer and mix for 5 minutes at 80℃ and a rotor speed of 30rpm. Then add the mixed slurry prepared in step 5, reduce the rotor speed of the mixer to 50g of the original speed, and continue mixing for 3 minutes. Discharge the rubber to obtain the compound. Take an appropriate amount of the compound and use a rotorless vulcanizing apparatus to determine its vulcanization curve according to ASTM D5289 standard under test conditions of 160℃, 1.67Hz, and ±0.5° arc. The positive vulcanization time T90 is found to be 10 minutes. Step 7: Place the rubber compound in a mold, apply a constant magnetic field with an intensity of 0.1T perpendicular to the molding direction (for 5 minutes), and perform compression molding and vulcanization at a temperature of 150°C and a pressure of 10MPa to obtain a glass fiber reinforced rubber composite material.

[0023] Comparative Example 3: The difference between this comparative example and Example 1 is that step 5, "pre-mixed slurry", is omitted. All solid components, such as surface-modified glass fiber and functional additives, are mixed with all natural rubber and fillers in a one-step high-intensity mixing process in an internal mixer.

[0024] A method for preparing a glass fiber reinforced rubber composite material includes the following steps: Step 1: Add 10.0g of boron nitride powder (5μm in diameter) to 100mL of anhydrous ethanol and ultrasonically disperse for 30min to form a suspension; separately add 0.3g of silane coupling agent (KH550) to 100mL of ethanol-water mixed solvent (pH 4.0) for hydrolysis for 45min; then add the hydrolysate dropwise to the suspension and reflux at 80℃ for 6h; after the reaction is completed, filter, wash with ethanol and deionized water, vacuum dry at 90℃ for 12h, and grind through a 200-mesh sieve to obtain surface-modified boron nitride; Step 2: Dissolve γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in 95% ethanol solution at a mass ratio of 1:0.5 to prepare a complex coupling agent solution. Step 3: The components and dosage of the compounding agents in the vulcanization system are the same as in Example 1; Step 4: Immerse 10g of short glass fibers (10μm in diameter and 3mm in length) in a complex coupling agent solution, remove and dry to obtain surface-modified glass fibers; Step 5: Add surface-modified glass fiber, 100g natural rubber, 1g carboxyl-terminated liquid nitrile rubber, 2g functional additives, 3g vulcanization system compounding agent, and 20g N330 carbon black into a mixing mill and mix for 8 minutes at 80℃ and a rotor speed of 30rpm to obtain a compound. Take an appropriate amount of the compound and use a rotorless vulcanizer to determine its vulcanization curve according to ASTM D5289 standard under test conditions of 160℃, 1.67Hz, and ±0.5° arc. The positive vulcanization time T90 is found to be 10 minutes. Step 6: Place the rubber compound in a mold, apply a constant magnetic field with an intensity of 0.1T perpendicular to the molding direction (for 5 minutes), and perform compression molding and vulcanization at a temperature of 150°C and a pressure of 10MPa to obtain a glass fiber reinforced rubber composite material.

[0025] Performance testing 1. Static mechanical property testing The static mechanical properties (tensile strength, elongation at break, stress at 100% elongation, and stress at 300% elongation) of the composite material were tested according to GB / T 528-2009 standard.

[0026] Table 1 Static mechanical performance test results

[0027] As shown in Table 1, the example group exhibits significant advantages in tensile strength and stress at a given elongation. This is fundamentally due to the synergistic reinforcing effect of the composite coupling agent, liquid interface compatibilizer, and pre-mixed slurry. After hydrolysis and condensation on the fiber surface, the composite coupling agent forms strong Si-O-Si bonds with the silanol groups on the fiber surface. Its terminal amino and epoxy groups also react in the interfacial region, forming a cross-linked, strong chemical coupling network. This network can simultaneously react with unsaturated double bonds, carboxyl groups, and other active groups in the rubber matrix, thus achieving a high-strength, high-modulus chemical bridging from the fiber to the matrix, greatly improving tensile strength and stress at a given elongation. The liquid interface compatibilizer has a low molecular weight and high fluidity, allowing it to fully penetrate and encapsulate the surface and surrounding area of ​​the fiber modified by the coupling agent. Its terminal active functional groups participate in the interfacial reaction, enabling the composite material to maintain high strength while retaining a good level of elongation at break. In contrast, Comparative Example 1 lacks the dense cross-linked interfacial layer formed by the composite coupling agent, resulting in insufficient interfacial chemical bonding strength and decreased stress transfer efficiency.

[0028] 2. Tear strength test The tear strength of the composite material was tested according to GB / T 529-2008 standard.

[0029] Table 2 Tear strength test results

[0030] As shown in Table 2, the tear strength of the example group was significantly higher than that of the comparative group. This is mainly due to the synergistic effect of the complex coupling agent and the liquid interface compatibilizer in this invention, which constructs a strong and tough chemical-physical interface layer between the glass fiber and the rubber matrix. This interface layer can effectively transfer and disperse tear stress, preventing cracks from propagating rapidly along the fragile interface. Comparative Example 1 used a single coupling agent, resulting in a weak interfacial chemical bonding network, making the interface the preferred path for stress concentration and crack propagation. Comparative Example 2 lacked a liquid interface compatibilizer, resulting in insufficient flexibility and toughening of the interface layer, which could not effectively buffer and dissipate tear energy. The one-step mixing in Comparative Example 3 led to severe fiber breakage and agglomeration, resulting not only in the loss of effective reinforcing length but also in the formation of numerous stress defect points, greatly reducing the material's tear resistance.

[0031] 3 Dynamic compression heat generation test The dynamic fatigue properties and heat generation of the composite material were tested according to ASTM D623.

[0032] Table 3 Results of dynamic compression heat generation test

[0033] As shown in Table 3, the compression heat generation ΔT in the example group ranged from 18.4 to 22.3°C, and the compression set ranged from 4.2% to 5.6%. This was mainly because the "pre-mixed slurry" process effectively protected the fiber aspect ratio and achieved uniform dispersion. Simultaneously, the composite coupling agent and liquid interface compatibilizer jointly constructed a strong and tough interfacial phase, significantly improving the stress transfer efficiency and uniformity within the composite material. This reduced internal friction and hysteresis losses under dynamic loads, resulting in lower heat generation and compression set. The comparative examples, lacking any of the above factors, exhibited increased heat generation and compression set.

[0034] 4. Thermal conductivity test The thermal conductivity of the composite material was tested according to ASTM E1461.

[0035] Table 4 Thermal conductivity test results

[0036] Table 4 shows that all examples exhibit high thermal conductivity, primarily because the pre-mixed slurry, under mild shear conditions, achieves highly uniform dispersion and good orientation of lamellar boron nitride in the rubber matrix. This, combined with glass fibers, forms a highly efficient three-dimensional thermal conductivity network, significantly improving the overall thermal conductivity of the composite material. In Comparative Example 1, the single coupling agent treatment failed to form a sufficiently dense interfacial layer, affecting the interfacial heat transfer efficiency between boron nitride and the matrix. The lack of compatibilizing and bridging effects from the liquid interfacial compatibilizer resulted in greater interfacial thermal resistance between boron nitride and the rubber matrix. In Comparative Example 3, high-shear mixing led to severe agglomeration of boron nitride and fiber breakage, disrupting the continuity and integrity of the thermal conductivity network and obstructing the thermal conductivity pathways.

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a glass fiber reinforced rubber composite material, characterized in that, Includes the following steps: Step 1: Immerse the glass fiber in a composite coupling agent solution, remove it and dry it to obtain surface-modified glass fiber; Step 2: Surface-modified glass fibers, a portion of the rubber matrix, liquid interface compatibilizer, and functional additives are mixed at high speed in a sealed container at 60-90°C to prepare a uniformly dispersed fiber slurry; wherein the portion of the rubber matrix accounts for 20%-40% of the total mass of the rubber matrix; Step 3: Add the remaining rubber matrix, vulcanization system compounding agent and reinforcing filler into the internal mixer and mix at 80-120℃ and rotor speed of 30-80rpm for 2-5 minutes. Then add the mixed slurry obtained in step 2 and continue mixing for 3-8 minutes. Discharge the rubber to obtain the compound. Step 4: Place the rubber compound in a mold and perform compression molding and vulcanization at a temperature of 150-180℃ and a pressure of 10-20MPa. The vulcanization time is the positive vulcanization time T90 of the rubber compound to obtain a glass fiber reinforced rubber composite material.

2. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, In step 1, the glass fiber is chopped glass fiber with a length of 3-15 mm and a diameter of 10-20 μm, and its addition amount is 10%-50% of the total mass of the rubber matrix.

3. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, The complex coupling agent solution in step 1 contains an aminosilane coupling agent and an epoxysilane coupling agent, with a mass ratio of 1:(0.5-2).

4. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, In step 2, the liquid interface compatibilizer is a carboxyl-terminated liquid nitrile rubber or an epoxy-terminated liquid nitrile rubber, and its addition amount is 1%-5% of the total mass of the rubber matrix.

5. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, In step 2, the functional additive is boron nitride that has been surface-treated with a silane coupling agent, with a flake diameter of 5-30 μm, and the amount added is 2%-8% of the total mass of the rubber matrix.

6. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, In step 2, the high-speed stirring speed is 800-2000 rpm, and the mixing time is 10-30 min.

7. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, In step 3, the compounding agent in the vulcanization system accounts for 3%-15% of the total mass of the rubber matrix; the reinforcing filler accounts for 20%-80% of the total mass of the rubber matrix.

8. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, After adding the mixed slurry in step 3, the rotor speed of the internal mixer is reduced to 50%-70% of the original speed.

9. The method for preparing the glass fiber reinforced rubber composite material according to claim 1, characterized in that, In step 4, a constant magnetic field with an intensity of 0.1-0.5T perpendicular to the molding direction is applied in the early stage of compression molding, and the duration is 33%-50% of the total molding time.

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