Phase change microcapsule modified self-repairing anti-aging rubber product derived elastomer and preparation method thereof

Abstract

The invention provides a phase-change microcapsule modified self-repairing anti-aging rubber product derived elastomer and a preparation method thereof.The method comprises the following steps that S1, a rubber product is prepared into decrosslinked rubber powder within a specific particle size range through a force-induced solid-phase chemical technology and a desulfurization technology; s2, dispersing the self-repairing factor serving as a core material in a mixed solution composed of a wall material and a dissolving agent for emulsification to prepare a phase change microcapsule with a self-repairing function; s3, mixing the decrosslinked rubber powder obtained in the step S1 and the phase change microcapsules obtained in the step S2 with raw rubber, a strength enhancer, a cross-linking agent and an accelerant to generate three-dimensional cross-linking, so as to prepare the phase change microcapsule modified self-repairing anti-aging rubber product derived elastomer. The elastomer prepared by the invention has the characteristics of large specific surface area, excellent tensile strength and tear strength, rapid and automatic healing, mechanical durability and the like, and is a sealant, a modifier and a shock pad material with excellent weather resistance for traffic engineering and civil construction.

Description

Technical Field

[0001] The invention relates to the field of solid waste resource recycling and microcapsule modified engineering materials, and in particular to a phase change microcapsule modified self-repairing aging-resistant rubber product derived elastomer and a preparation method thereof. Background Art

[0002] Rubber materials are widely used in the fields of construction, communication, transportation, national defense, medical treatment and daily necessities due to their low cost, easy processing, excellent insulation, low density and high specific strength. However, rubber materials are prone to aging and failure due to external forces, environment and other factors during use, especially microcracks are prone to occur on the surface and inside of the material, resulting in performance degradation and shortened life. If the rubber material is given the ability to self-repair microcracks and inhibit crack propagation, its service life will be effectively extended and safety and reliability will be improved.

[0003] Inspired by the biological self-repair mechanism, scientists have introduced the concept of self-repair into the field of polymer materials, and achieved autonomous repair of material microcracks by simulating the damage repair principle of organisms. Self-repairing materials can be divided into two major systems based on the repair mechanism: intrinsic type and external aid type: the intrinsic type relies on reversible chemical reactions inside the material to achieve repair; the external aid type is achieved through pre-set repair agents, mainly including liquid core fiber type and microcapsule type. Compared with the liquid core fiber system, microcapsule technology has been industrialized, and it has more application advantages in microcrack perception, packaging convenience and composite process maturity.

[0004] Microencapsulation, or microcapsule technology, refers to a method of using monomers or other substances with specific functions as core materials, isolating them from the external environment and encapsulating them in a tiny container. With the development of modern science and technology, researchers use the principle of bionic self-repair to achieve self-repair of substrates through active modes to improve the structural properties of the matrix material. This technology imitates the mechanism of biological tissues automatically secreting healing substances to the damaged area, allowing the damaged area to be repaired.

[0005] Adding a repair agent wrapped in fibers or microcapsules to the traditional substrate components, when cracks appear in the substrate, the capillary force generated by the microcracks will cause the additive to rupture, release the repair agent and penetrate into the cracks, thereby repairing the damage and preventing the cracks from expanding, forming an active repair network system inside the substrate. Microcapsule self-repair technology provides a new way to repair microcracks in materials, without the need for additional manual monitoring and high surface maintenance costs, which can not only extend the life of the substrate structure, but also save the operating expenses of building materials. As an important component of the self-repairing substrate material structure, this technology has broad application prospects in future civil engineering construction and repair fields.

[0006] As an emerging research direction in the field of intelligent materials, the microcapsule self-healing technology aims to achieve low cost, automation, and intelligence, showing broad development and application prospects. However, the popularization and application of this technology still face many challenges: (1) Traditional experimental methods and testing means are difficult to deeply study the composition and self-healing behavior of microcapsules. The formulation design, repair mechanism, effects, and influence laws of structural properties are still in the experimental exploration stage. The construction of microscopic models and theoretical systems is still immature, lacking systematic theoretical support. (2) Under the existing production technology, the yield of microcapsules is low, the cost is high, and there are limitations such as insufficient storage stability and narrow repair range, which hinder the technology maturity, industrial production, and practical application promotion. (3) The content of the repair agent in the microcapsules is limited, and it does not have the function of recycling. It cannot achieve multiple self-healings of materials and structures. Moreover, "holes" are easily formed in the original microcapsule area after repair, increasing the risk of structural defects, which limits the technology application to a certain extent. (4) The traditional microcapsule self-healing technology relying on single mechanical or chemical responses has difficulty meeting the self-healing requirements under the coupling action of multiple factors in the actual service environment, which is also an important reason for its lag in practical engineering applications.

[0007] Preparing elastomers with self-healing functions by combining microcapsules with rubber has broad application prospects in fields such as civil engineering, aerospace, automotive industry, and medical equipment. For example, in civil engineering, self-healing concrete can significantly extend the service life of buildings and reduce maintenance costs; in the aerospace field, self-healing materials can improve the safety and reliability of aircraft; in the automotive industry, self-healing rubber can be used to manufacture more durable tires and components; in medical equipment, self-healing materials can improve the service life and safety of equipment. By continuously optimizing the microcapsule self-healing technology and overcoming existing challenges, this technology is expected to be widely applied in more fields, bringing new breakthroughs to materials science and engineering applications. Summary of the Invention

[0008] The purpose of the present invention is to prepare a phase change microcapsule-modified self-healing and anti-aging rubber product-derived elastomer. The technical problem to be solved by the present invention is to overcome the existing technical bottleneck of the low recycling rate and poor cycle regeneration feasibility of waste rubber products, and provide a synthetic method that can efficiently solve crosslinking and composite high-performance phase change microcapsules to recycle waste rubber products, improve the melt processability and self-healing and anti-aging ability of waste rubber products, so as to expand its application in multi-functional integrated rubber product-derived elastomers.

[0009] To achieve the above object, the present invention provides a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer and a preparation method thereof. In the present invention, rubber products are processed through a mechanochemical technology and a desulfurization process to prepare crosslinked rubber powder with a specific particle size range; a self-healing factor is emulsified as a core material dispersed in a mixed solution composed of a wall material and a solvent to prepare self-healing functional phase change microcapsules; the obtained crosslinked rubber powder and phase change microcapsules are mixed with virgin rubber, a strength enhancer, a crosslinking agent, and an accelerator to undergo three-dimensional crosslinking to prepare a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer.

[0010] According to the first aspect of the present invention, there is provided a method for preparing a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer, including the following steps: Step S1, rubber products are processed through a mechanochemical technology and a desulfurization process to prepare crosslinked rubber powder with a specific particle size range; Step S2, a core material is emulsified and dispersed in a mixed solution composed of a wall material and a solvent to prepare self-healing functional phase change microcapsules; Step S3, the crosslinked rubber powder obtained in Step S1 and the phase change microcapsules obtained in Step S2 are mixed with virgin rubber, a strength enhancer, a crosslinking agent, and an accelerator to undergo three-dimensional crosslinking to prepare a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer.

[0011] Preferably, in Step S1, the rubber products are waste rubber products, including one or more of composite tires, natural rubber tires, synthetic rubber tires, multi-layer tires, industrial rubber hoses, rubber sheets, and medical rubber products.

[0012] Preferably, in Step S1, the mechanochemical technology is one or more of a vibration mill mechanochemical pulverization method, a ball mill mechanochemical treatment method, an impact mill mechanochemical pulverization method, a low-temperature mechanochemical pulverization method, and a force-chemical synergistic pulverization method.

[0013] Preferably, in Step S1, the mechanochemical technology is a vibration mill mechanochemical pulverization method, and the technical parameters are: the mass ratio of balls to materials is 8:1 to 12:1, the pulverization time is 30 to 60 min, the frequency is 15 to 30 Hz, and the amplitude is 5 to 10 mm.

[0014] Preferably, in Step S1, the mechanochemical technology is a ball mill mechanochemical treatment method, and the technical parameters are: the rotation speed is 400 to 800 r / min, the ball-to-material ratio is 5:1 to 15:1, and the material filling rate is 50 to 70%.

[0015] Preferably, in Step S1, the mechanochemical technology is an impact mill mechanochemical pulverization method, and the technical parameters are: the linear velocity is 80 to 150 m / s, and the pulverization time is 10 to 30 min.

[0016] Preferably, in step S1, the mechanochemical technology is a low-temperature mechanochemical pulverization method, and the technical parameters are as follows: the refrigerant is one or more of liquid nitrogen, carbon dioxide, ethanol, and toluene, and the freezing time is 5 to 25 min.

[0017] Preferably, in step S1, the desulfurization technology is one or more of mechanical desulfurization, microwave desulfurization, high-temperature pyrolysis desulfurization, solvent desulfurization, regenerant desulfurization, microwave-assisted chemical desulfurization, ultrasonic-assisted solvent desulfurization, microbial desulfurization, supercritical fluid desulfurization, and plasma desulfurization.

[0018] Preferably, in step S1, the desulfurization technology is mechanical desulfurization, and the technical parameters are as follows: the mass ratio of the balls to the material is 10:1 to 20:1, the rotation speed is 300 to 800 rpm, the treatment time is 30 to 120 min, and the temperature is 0 to 80 °C.

[0019] Preferably, in step S1, the desulfurization technology is microwave desulfurization, and the technical parameters are as follows: the microwave power is 500 to 1500 W, the treatment time is 5 to 20 min, and the temperature is 150 to 250 °C.

[0020] Preferably, in step S1, the desulfurization technology is high-temperature pyrolysis desulfurization, and the technical parameters are as follows: the temperature is 200 to 400 °C, the time is 30 to 120 min, and the atmosphere is one or more of nitrogen, helium, argon, and neon.

[0021] Preferably, in step S1, the desulfurization technology is microwave-assisted chemical desulfurization, and the technical parameters are as follows: the microwave power is 800 to 1200 W, the treatment time is 10 to 15 min, and the temperature is 180 to 200 °C.

[0022] Preferably, the particle size distribution of the crosslinking-decoupled rubber powder obtained in step S1 is 75 to 180 μm, and the residual sulfur content is less than 1.5%.

[0023] Preferably, in step S2, the core material is one or more of polyurea formaldehyde, epoxy resin, polymethyl methacrylate, polyurea, ethyl cellulose, disulfide oligomer, and methyltrimethoxysilane.

[0024] Preferably, in step S2, the wall material is one or more of gelatin-arabic gum, chitosan, polyvinyl alcohol, sodium alginate, paraffin, and silica coating; in step S2, the dissolving agent is one or more of water, methanol, ethanol, acetone, dichloromethane, chloroform, tetrahydrofuran, N,N-dimethylformamide, and N-methylpyrrolidone.

[0025] Preferably, in step S2, the mass ratio of the core material to the wall material is 2:1 to 3:1, the total mass of the core material and the wall material accounts for 10% to 30% of the mass fraction of the mixed solution, and the emulsification conditions are as follows: the time is 10 to 120 min, the temperature is 0 to 80 °C, and the pH value is 2 to 12.

[0026] Preferably, in step S3, the raw rubber is one or more of natural rubber, styrene-butadiene rubber, cis-butadiene rubber, butyl rubber, ethylene-propylene-diene monomer rubber, nitrile rubber, chloroprene rubber, polyurethane rubber, and recycled rubber; in step S3, the strength enhancer is one or more of carbon black, silica, metal oxide, mineral filler, nano-inorganic filler, and organic filler; in step S3, the crosslinking agent is one or more of ordinary sulfur, insoluble sulfur, dicumyl peroxide, di-tert-butyl peroxide, and phenolic resin; in step S3, the accelerator is one or more of N-cyclohexyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, diphenylguanidine, di-o-tolylguanidine, N-tert-butyl-2-benzothiazole sulfenamide, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, and zinc dimethyldithiocarbamate.

[0027] Preferably, in step S3, the mass fraction of the de-crosslinked rubber powder in the elastomer is 10% to 50%, the mass fraction of the phase change microcapsule in the elastomer is 5% to 30%, the mass fraction of the raw rubber in the elastomer is 20% to 80%, the mass fraction of the strength enhancer in the elastomer is 5% to 20%, the mass fraction of the crosslinking agent in the elastomer is 1% to 10%, and the mass fraction of the accelerator in the elastomer is 0.5% to 5%.

[0028] Preferably, in step S3, the three-dimensional crosslinking conditions are as follows: the temperature is 100 to 180 °C, the time is 10 to 120 min, and the pressure is 2 to 20 MPa.

[0029] To achieve the above object, according to the second aspect of the present invention, the present invention also provides an elastomer obtained by the foregoing preparation method.

[0030] Preferably, the specific surface area of the obtained elastomer is 36 m 2 / g to 48 m 2 / g, the tensile strength is 8 to 15 MPa, the tear strength is 40 to 58 kN / m, the self-healing time is 30 to 60 min, and the aging mass loss rate is 3 to 7%.

[0031] The beneficial effects of the present invention are as follows: (1) Through the force-induced solid-phase chemical technology and desulfurization process, rubber products are processed and derived into crosslinking-degraded rubber powders with specific particle sizes and diameters, rich pore properties, and large specific surface areas; (2) Phase change microcapsules are prepared with self-healing factors as the core material, forming a filler with special functions combined with rubber, endowing the elastomer with rapid self-healing ability; (3) When preparing the elastomer material, a strength enhancer with enhanced mechanical and mechanical properties is added to endow it with excellent tensile strength, tear strength, durability, and cyclic service life; (4) Through the optimization of the synthesis process, the prepared elastomer has characteristics such as a large specific surface area, excellent tensile strength and elongation at break, rapid automatic healing, and mechanical durability, and can be used for the production of sealants, modifiers, and shock-absorbing cushion materials for traffic engineering and civil construction with excellent weather resistance.

[0032] The technical solution proposed by the present invention enables the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer to have characteristics such as a large specific surface area, excellent tensile strength and elongation at break, rapid automatic healing, and mechanical durability. The technical problem to be solved by the present invention is to overcome the existing technical bottleneck of the low recycling rate of waste rubber products and the poor feasibility of cyclic regeneration, and to provide a synthesis method that can solve the above deficiencies in the material technology in the field of cyclic regeneration of existing solid waste resources, and can efficiently crosslink and compound high-performance phase change microcapsules to realize the recycling of waste rubber products, improve the melt processability and self-healing and aging-resistant ability of waste rubber products, so as to expand its application in the elastomer derived from multifunctional integrated rubber products, and has broad application potential and market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a schematic flow chart of the method of the present invention.

[0035] Figure 2 It is a scanning electron microscope image of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer in Example 1.

[0036] Figure 3 It is a particle size distribution curve of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer in Example 1.

[0037] Figure 4 It is a scanning electron microscope image of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer in Example 2.

[0038] Figure 5 It is a scanning electron microscope image of the elastomer derived from the phase change microcapsule modified self-healing and aging-resistant rubber product in Example 3.

[0039] Figure 6 It is a scanning electron microscope image of the elastomer derived from the phase change microcapsule modified self-healing and aging-resistant rubber product in Example 4. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The present invention will be described in detail below in conjunction with embodiments.

[0041] As Figure 1 shown, Embodiment 1 of the present invention provides a preparation method of an elastomer derived from a phase change microcapsule modified self-healing and aging-resistant rubber product, including the following steps: Step S11, preparing de-crosslinked rubber powder: subjecting a composite tire to a vibration mill force-induced solid-phase chemical pulverization method (the mass ratio of balls to materials is 10:1, the pulverization time is 30 min, the frequency is 20 Hz, and the amplitude is 8 mm) and a mechanical desulfurization process (the mass ratio of balls to materials is 12:1, the rotation speed is 400 rpm, the treatment time is 40 min, and the temperature is 20°C) to prepare de-crosslinked rubber powder within a specific particle size range (the particle size distribution is 75 μm, and the residual sulfur content is 1.0%); Step S12, preparing self-healing functional phase change microcapsules: dispersing polyurea formaldehyde in a mixed solution composed of gelatin-arabic gum and water (the mass ratio of polyurea formaldehyde to gelatin-arabic gum is 2:1, and the total mass of polyurea formaldehyde and gelatin-arabic gum accounts for 15% of the mass fraction of the mixed solution), emulsifying for 60 min at 25°C and a pH of 7 to prepare self-healing functional phase change microcapsules; Step S13, preparing an elastomer derived from a phase change microcapsule modified self-healing and aging-resistant rubber product: mixing the de-crosslinked rubber powder obtained in Step S11 and S12 (the mass fraction in the elastomer is 15%) and the phase change microcapsules (the mass fraction in the elastomer is 10%) with styrene-butadiene rubber (the mass fraction in the elastomer is 61%), carbon black (the mass fraction in the elastomer is 8%), ordinary sulfur (the mass fraction in the elastomer is 4%) and N-cyclohexyl-2-benzothiazole sulfenamide (the mass fraction in the elastomer is 2%), and performing three-dimensional crosslinking at 120°C / 5 MPa for 30 min to prepare an elastomer derived from a phase change microcapsule modified self-healing and aging-resistant rubber product. The specific surface area of the obtained elastomer is 48 m 2 / g, the tensile strength is 15 MPa, the tear strength is 58 kN / m, the self-healing time is 30 min, and the aging mass loss rate is 3%.

[0042] As Figure 2 shown, the scanning electron microscope image of the phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer obtained in Example 1 of the present invention shows that the elastomer exhibits a smaller particle size, uniform dispersion among particles, and no obvious agglomeration and accumulation between particles, which is beneficial to fully expose the specific surface area and pore properties.

[0043] As Figure 3 shown, the particle size distribution curve of the phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer obtained in Example 1 of the present invention shows that the particle size distribution of the elastomer is uniform and there are no large amounts of irregular particles.

[0044] Example 2 of the present invention provides a preparation method of a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer, including the following steps: Step S21, preparing crosslinking-degraded rubber powder: subjecting a synthetic rubber tire to ball milling force-induced solid-phase chemical treatment (rotation speed of 400 r / min, ball-to-material ratio of 8:1, material filling rate of 60%) and microwave desulfurization (microwave power of 800 W, treatment time of 10 min, temperature of 180 °C) to prepare crosslinking-degraded rubber powder within a specific particle size range (particle size distribution of 100 μm, residual sulfur content of 1.2%); Step S22, preparing self-healing functional phase change microcapsules: dispersing epoxy resin in a mixed solution composed of chitosan and methanol (mass ratio of epoxy resin to chitosan is 3:1, and the total mass of epoxy resin and chitosan accounts for 10% of the mass fraction of the mixed solution), emulsifying at 0 °C and pH of 5 for 20 min to prepare self-healing functional phase change microcapsules; Step S23, preparing a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer: mixing the crosslinking-degraded rubber powder obtained in Step S21 (mass fraction in the elastomer is 20%) and the phase change microcapsules (mass fraction in the elastomer is 13%) with natural rubber (mass fraction in the elastomer is 59%), silica (mass fraction in the elastomer is 5%), insoluble sulfur (mass fraction in the elastomer is 2%) and 2-mercaptobenzothiazole (mass fraction in the elastomer is 1%), and performing three-dimensional crosslinking at 100 °C / 3 MPa for 20 min to prepare a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer. The specific surface area of the obtained elastomer is 44 m 2 / g, the tensile strength is 12 MPa, the tear strength is 53 kN / m, the self-healing time is 40 min, and the aging mass loss rate is 4%.

[0045] As Figure 4As shown, the scanning electron microscope image of the phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer obtained in Example 2 of the present invention shows that the elastomer exhibits a smaller particle size, uniform dispersion among particles, and no obvious agglomeration and accumulation between particles, which is beneficial to fully expose the specific surface area and pore properties.

[0046] Example 3 of the present invention provides a preparation method of a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer, including the following steps: Step S31, preparing crosslinking-degraded rubber powder: subjecting a synthetic rubber tire to impact grinding force-induced solid-phase chemical pulverization (linear velocity of 100 m / s, pulverization time of 20 min) and high-temperature pyrolysis desulfurization (temperature of 280 °C, time of 50 min, atmosphere of nitrogen) to prepare crosslinking-degraded rubber powder within a specific particle size range (particle size distribution of 120 μm, residual sulfur content of 1.3%); Step S32, preparing self-healing functional phase change microcapsules: dispersing polymethyl methacrylate in a mixed solution composed of polyvinyl alcohol and ethanol (mass ratio of polymethyl methacrylate to polyvinyl alcohol is 2:1, and the total mass of polymethyl methacrylate and polyvinyl alcohol accounts for 18% of the mass fraction of the mixed solution), emulsifying at 40 °C and pH of 8 for 80 min to prepare self-healing functional phase change microcapsules; Step S33, preparing a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer: mixing the crosslinking-degraded rubber powder obtained in Step S31 and S32 (mass fraction in the elastomer is 20%) and the phase change microcapsules (mass fraction in the elastomer is 15%) with cis-butadiene rubber (mass fraction in the elastomer is 46%), metal oxide (zinc oxide) (mass fraction in the elastomer is 10%), dicumyl peroxide (mass fraction in the elastomer is 6%) and dibenzothiazole disulfide (mass fraction in the elastomer is 3%), and performing three-dimensional crosslinking at 150 °C / 8 MPa for 60 min to prepare a phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer. The specific surface area of the obtained elastomer is 39 m 2 / g, the tensile strength is 10 MPa, the tear strength is 46 kN / m, the self-healing time is 50 min, and the aging mass loss rate is 5%.

[0047] As Figure 5 shown, the scanning electron microscope image of the phase change microcapsule modified self-healing and aging-resistant rubber product-derived elastomer obtained in Example 3 of the present invention shows that the elastomer exhibits a smaller particle size, uniform dispersion among particles, and no obvious agglomeration and accumulation between particles, which is beneficial to fully expose the specific surface area and pore properties.

[0048] Example 4 of the present invention provides a preparation method of a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer, including the following steps: Step S41, preparing de-crosslinked rubber powder: Multilayer tires are subjected to cryogenic force-induced solid-phase chemical pulverization (the refrigerant is liquid nitrogen, and the freezing time is 15 min) and microwave-assisted chemical desulfurization (the microwave power is 800 W, the treatment time is 15 min, and the temperature is 180 °C) to prepare de-crosslinked rubber powder with a specific particle size range (the particle size distribution is 140 μm, and the residual sulfur content is 1.5%); Step S42, preparing self-healing functional phase change microcapsules: Methyltrimethoxysilane is dispersed in a mixed solution composed of sodium alginate and dichloromethane (the mass ratio of methyltrimethoxysilane to sodium alginate is 3:1, and the total mass of methyltrimethoxysilane and sodium alginate accounts for 20% of the mass fraction of the mixed solution), and emulsified at 60 °C and pH 9 for 90 min to prepare self-healing functional phase change microcapsules; Step S43, preparing a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer: The de-crosslinked rubber powder obtained in Step S41 (the mass fraction in the elastomer is 25%) and the phase change microcapsules (the mass fraction in the elastomer is 18%) are mixed with butyl rubber (the mass fraction in the elastomer is 33%), mineral filler (calcium carbonate) (the mass fraction in the elastomer is 12%), phenolic resin (the mass fraction in the elastomer is 8%), and tetramethylthiuram disulfide (the mass fraction in the elastomer is 4%), and three-dimensional crosslinking occurs at 170 °C / 10 MPa for 90 min to prepare a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer. The specific surface area of the obtained elastomer is 36m 2 / g, the tensile strength is 8 MPa, the tear strength is 40 kN / m, the self-healing time is 60 min, and the aging mass loss rate is 7%.

[0049] As Figure 6 shown, the scanning electron microscope image of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer obtained in Example 4 of the present invention shows that the elastomer exhibits a smaller particle size, uniform dispersion among particles, and no obvious agglomeration and accumulation between particles, which is beneficial to fully expose the specific surface area and pore properties.

[0050] Comparative Example 1 of the present invention provides a preparation method of a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer, and basically uses the method of Example 1 to prepare the elastomer. The difference is that in this example, the force-induced solid-phase chemistry technology is not used to pretreat the rubber product to prepare the elastomer. Specifically, the composite tire is desulfurized by a mechanical method (the mass ratio of the ball to the material is 12:1, the rotation speed is 400 rpm, the treatment time is 40 min, and the temperature is 20 °C) to prepare crosslinked rubber powder with a specific particle size range; polyurea formaldehyde is dispersed in a mixed solution composed of gelatin-arabic gum and water (the mass ratio of polyurea formaldehyde to gelatin-arabic gum is 2:1, and the total mass of polyurea formaldehyde and gelatin-arabic gum accounts for 15% of the mass of the mixed solution), and emulsified at 25 °C and pH 7 for 60 min to prepare self-healing functional phase change microcapsules; the obtained crosslinked rubber powder (mass fraction in the elastomer is 15%) and phase change microcapsules (mass fraction in the elastomer is 10%) are mixed with styrene-butadiene rubber (mass fraction in the elastomer is 61%), carbon black (mass fraction in the elastomer is 8%), ordinary sulfur (mass fraction in the elastomer is 4%) and N-cyclohexyl-2-benzothiazole sulfenamide (mass fraction in the elastomer is 2%), and three-dimensional crosslinking occurs at 120 °C / 5 MPa for 30 min to prepare a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer.

[0051] Comparative Example 2 of the present invention provides a preparation method of a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer, and basically uses the method of Example 2 to prepare the elastomer. The difference is that in this example, the phase change microcapsules with self-healing function are not used to prepare the elastomer. Specifically, the synthetic rubber tire is treated by ball milling force-induced solid-phase chemistry (rotation speed is 400 r / min, ball-to-material ratio is 8:1, and material filling rate is 60%) and microwave desulfurization (microwave power is 800 W, treatment time is 10 min, and temperature is 180 °C) to prepare crosslinked rubber powder with a specific particle size range (particle size distribution is 100 μm, and residual sulfur content is 1.2%); the obtained crosslinked rubber powder (mass fraction in the elastomer is 20%), natural rubber (mass fraction in the elastomer is 72%), white carbon black (mass fraction in the elastomer is 5%), insoluble sulfur (mass fraction in the elastomer is 2%) and 2-mercaptobenzothiazole (mass fraction in the elastomer is 1%) are mixed, and three-dimensional crosslinking occurs at 100 °C / 3 MPa for 20 min to prepare a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer.

[0052] Comparative Example 3 of the present invention provides a method for preparing a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer, which basically adopts the method of Example 3 to prepare the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer. The difference is that in this example, no strength enhancer is used to prepare the elastomer. Specifically, the synthetic rubber tire is subjected to impact mill force-induced solid-phase chemical pulverization (linear velocity is 100 m / s, pulverization time is 20 min) and high-temperature pyrolysis desulfurization (temperature is 280 °C, time is 50 min, atmosphere is nitrogen) to prepare crosslinked rubber powder with a specific particle size range (particle size distribution is 120 μm, residual sulfur content is 1.3%); polymethyl methacrylate is dispersed in a mixed solution composed of polyvinyl alcohol and ethanol (mass ratio of polymethyl methacrylate to polyvinyl alcohol is 2:1, and the total mass of polymethyl methacrylate and polyvinyl alcohol accounts for 18% of the mass fraction of the mixed solution), and emulsified at 40 °C and pH 8 for 80 min to prepare self-healing functional phase change microcapsules; the obtained crosslinked rubber powder (mass fraction in the elastomer is 20%) and phase change microcapsules (mass fraction in the elastomer is 15%) are mixed with cis-butadiene rubber (mass fraction in the elastomer is 56%), dicumyl peroxide (mass fraction in the elastomer is 6%) and dibenzothiazole disulfide (mass fraction in the elastomer is 3%), and three-dimensional crosslinking occurs at 150 °C / 8 MPa for 60 min to prepare the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer.

[0053] The structural characterization and performance testing are as follows.

[0054] Microscopic morphology testing: The field emission scanning electron microscope (model JSM-7900F, JEOL, Japan) was used to observe the microscopic structure of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer ( Figure 2 , Figure 4 , Figure 5 , Figure 6 ).

[0055] Particle size distribution testing: The laser particle size analyzer (model Mastersizer 2000, Malvern Panalytical, UK) was used to test the particle size distribution of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer ( Figure 3 ).

[0056] Free surface polymer chain percentage testing: X-ray photoelectron spectroscopy (model ESCALAB Xi+, Thermo Fisher Scientific, USA) was used to test the elemental composition and chemical state information of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer.

[0057] Tensile strength and elongation at break test: An electronic universal testing machine (model Instron 6800, Instron, USA) was used to test the mechanical strength and mechanical properties of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer.

[0058] Specific surface area test: A gas adsorption instrument (ASAP 2060, Micromeritics, USA) was used to test the nitrogen adsorption-desorption isotherm and pore size distribution curve of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer at 77 K.

[0059] Experimental results: As Figure 2 、 Figure 4 、 Figure 5 and Figure 6 shown, the synthesized phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer exhibited smaller particle sizes, uniform dispersion among particles, no obvious inter-particle agglomeration and accumulation, and a smooth surface, which was beneficial to fully expose the specific surface area and pore properties.

[0060] As Figure 3 shown, the synthesized phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer exhibited a uniform particle size distribution, and no large number of irregular particles, indicating that the de-crosslinked rubber powder derived from the effective treatment of rubber products by the force-induced solid-phase chemistry technology and the desulfurization process met the raw material use standard for recycling.

[0061] Table 1 compares the specific surface area, tensile strength, tear strength, self-healing time, and aging mass loss rate of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomers obtained in the examples and comparative examples.

[0062] Table 1

[0063] Examples 1 to 4 had a relatively large specific surface area (36 m 2 / g to 48 m 2 / g). This was because the rubber products were derivatively pretreated by combining the force-induced solid-phase chemistry technology and the desulfurization process to prepare rubber powder with a smooth surface, uniform dispersion among particles, and uniform particle size distribution, endowing the elastomer with a large specific surface area; the specific surface area of Comparative Example 1 was only 4 m 2 / g, which was due to the fact that the force-induced solid-phase chemistry technology was not used to crush and pretreat the rubber products, significantly affecting the expression of pore properties and the subsequent reaction degree.

[0064] The self-healing ability and aging resistance characteristics of the phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer are closely related to the specific surface area, mechanical and mechanical strength. The tensile strength of Examples 1 to 4 with a large specific surface area and high mechanical strength is above 8 MPa, the tear strength is above 40 kN / m, the self-healing time is below 60 min, and the aging mass loss rate is below 7%, showing good self-healing ability and aging resistance characteristics. Among them, Example 1 with the largest specific surface area and the best mechanical strength is the most excellent in the self-healing and aging resistance tests, with a tensile strength of 15 MPa, a tear strength of 58 kN / m, a self-healing time of 30 min, and an aging mass loss rate of 3%, far higher than Comparative Examples 1 to 3 with a small specific surface area and low mechanical strength (tensile strength ≤ 3 MPa, tear strength ≤ 10 kN / m, self-healing time ≥ 160 min, aging mass loss rate ≥ 12%).

[0065] The present invention provides a phase change microcapsule-modified self-healing and aging-resistant rubber product-derived elastomer and a preparation method thereof. There are many specific methods and ways to implement this technical solution. The above description is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by the prior art.

Claims

1. A method for preparing a phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer, characterized in that: The following steps are involved: Step S1, preparing de-crosslinked rubber powder by subjecting the rubber product to a mechanical solid phase chemical technology and a desulfurization process; Step S2, dispersing the core material in a mixed solution consisting of the wall material and the solvent for emulsification to prepare a self-repairing functional phase change microcapsule; Step S3, mixing the decrosslinked rubber powder obtained in step S1 and the phase change microcapsules obtained in step S2 with the original rubber, a strength enhancer, a crosslinking agent and an accelerator to undergo three-dimensional crosslinking to prepare a phase change microcapsule modified self-repairing aging-resistant rubber product derived elastomer.

2. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: The force-induced solid-phase chemical technology in step S1 is one or more of vibration grinding force-induced solid-phase chemical pulverization method, ball mill force-induced solid-phase chemical treatment method, impact grinding force-induced solid-phase chemical pulverization method, low-temperature force-induced solid-phase chemical pulverization method, and force-chemical synergistic pulverization method.

3. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: The desulfurization process in step S1 is one or more of mechanical desulfurization, microwave desulfurization, high-temperature pyrolysis desulfurization, solvent desulfurization, regeneration agent desulfurization, microwave-assisted chemical desulfurization, ultrasound-assisted solvent desulfurization, microbial desulfurization, supercritical fluid desulfurization, and plasma desulfurization processes; the particle size distribution of the decrosslinked rubber powder obtained in step S1 is 75-180 μm, and the residual sulfur content is less than 1.5%.

4. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: The core material in step S2 is one or more of polyurea formaldehyde, epoxy resin, polymethyl methacrylate, polyurea, ethyl cellulose, disulfide bond oligomer, and methyltrimethoxysilane.

5. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: In step S2, the wall material is one or more of gelatin-arabic gum, chitosan, polyvinyl alcohol, sodium alginate, paraffin, and silicon dioxide coating; the solvent is one or more of water, methanol, ethanol, acetone, dichloromethane, chloroform, tetrahydrofuran, N,N-dimethylformamide, and N-methylpyrrolidone.

6. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: In step S2, the mass ratio of the core material to the wall material is 2:1-3:1, the total mass of the core material and the wall material accounts for 10%-30% of the mass fraction of the mixed solution, and the emulsification conditions are: time is 10-120 min, temperature is 0-80°C, and pH value is 2-12.

7. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: In step S3, the virgin rubber is one or more of natural rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, EPDM rubber, nitrile rubber, chloroprene rubber, polyurethane rubber, and recycled rubber; the strength enhancer is one or more of carbon black, white carbon black, metal oxides, mineral fillers, nano inorganic fillers, and organic fillers; the crosslinking agent is one or more of ordinary sulfur, insoluble sulfur, diisopropylbenzene peroxide, di-tert-butyl peroxide, and phenolic resin; the accelerator is one or more of N-cyclohexyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, diphenylguanidine, di-o-tolylguanidine, N-tert-butyl-2-benzothiazole sulfenamide, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, and zinc dimethyldithiocarbamate.

8. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: In step S3, the mass fraction of the decrosslinked rubber powder in the elastomer is 10% to 50%, the mass fraction of the phase change microcapsules in the elastomer is 5% to 30%, the mass fraction of the virgin rubber in the elastomer is 20% to 80%, the mass fraction of the strength enhancer in the elastomer is 5% to 20%, the mass fraction of the crosslinking agent in the elastomer is 1% to 10%, and the mass fraction of the accelerator in the elastomer is 0.5% to 5%.

9. The method for preparing the phase-change microcapsule modified self-repairing aging-resistant rubber product derived elastomer according to claim 1, characterized in that: The conditions for the three-dimensional cross-linking in step S3 are: temperature of 100-180° C., time of 10-120 min, and pressure of 2-20 MPa.

10. An elastomer prepared by the method for preparing an elastomer derived from a phase-change microcapsule-modified self-repairing aging-resistant rubber product according to any one of claims 1 to 9.

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