Rubber Chains Research Articles

Prediction of Adhesion Friction Coefficient Using Two Different Models for Tire Tread Rubber Compounds

ABSTRACT Two proposed methods to determine the adhesion friction coefficient were validated by experimental results of two types of rubber compounds at different sliding velocities under dry conditions. The experimental results were measured from a linear friction tester, while the viscoelastic friction coefficient was estimated using the Persson's contact theory. Adhesive friction (model 1) was derived from the deconvolution of dry friction coefficient in two Gaussian-like curves. Interesting results were obtained using the deconvoluted method in the range of intermediate sliding velocities where preponderant contribution to the adhesion friction is replaced by the viscoelastic friction. Fitting parameter results were in good general agreement with values derived from the literature, confirming the influence of the mechanical properties of the compound and substrate texture on the proposed adhesion frictional method. The second adhesive friction model (model 2) was based on the confinement rheology of rubber chains on the contact with the asperities of the road surface. We demonstrated that acceptable adhesion friction results were achieved from a dynamic viscosity test at low frequencies, confirming the applicability of the proposed rheological model. Moreover, the relationship between the rubber composition and the modified contact layer along with the likely interphase reaction are also discussed.

Grafting of epoxidized natural rubber chains with BN platelets to obtain flexible and thermally conductive papers

Owing to the rapid development of high-power and minimized electronic devices, the materials with ultra-flexibility and effective heat dissipation have attracted much interest. Herein, the high thermally conductive epoxidized natural rubber (ENR) papers with layered structures based on boron nitride (BN) platelets are reported. First, polyrhodanine (PRd) was coated on the surface of BN platelets via oxidative polymerization of rhodanine (Rhd), which was initiated by the absorbed (S2O8)2- ions. Then, BN-PRd platelets were grafted with ENR chains using a mechanochemical method due to the presence of N–CS groups in PRd, allowing the combination of PRd and ENR chains with stable covalent bonds. Moreover, the grafted ENR chains acted as bridges between adjacent BN platelets and improved the heat transfer ability of BN-PRd/ENR thermally conductive composite papers. The as-prepared ultra-flexible 30 wt% BN-PRd/ENR thermally conductive composite papers rendered high in-plane (λ∥) and through-plane (λ⊥) thermal conductivity of 14.57 and 0.52 W/(mK), respectively, which were correspondingly 8094% and 289% of pure ENR paper (0.18 W/(mK)). Also, Young's modulus of the 30 wt% BN-PRd/ENR thermally conductive composite paper was 25.90 MPa. Overall, the as-fabricated BN-PRd/ENR thermally conductive composite papers demonstrated high flexibility, excellent mechanical robustness, outstanding thermal conductivity, and superior electronic illustration, indicating potential applications in areas of electronic components as thermal interface materials.

Poly (Lactic Acid)/Ground Tire Rubber Blends Using Peroxide Vulcanization.

Poly (Lactic Acid) (PLA)/Ground Tire Rubber (GTR) blends using Dicumyl peroxide (DCP) as a crosslinking agent were prepared with the following aims: propose a new route to recycle wastes rubber from the automotive industry and improve the toughness and impact strength of the inherently brittle bio-based PLA. The GTR were subjected to two types of grinding process (cryo- and dry ambient grinding). Swelling measurements revealed the grinding to be associated with a mechanical damage of the rubber chains, independently on the type of grinding or on the GTR size (from <400 µm to <63 µm). Moreover, the finest GTR contains the largest amount of reinforcing elements (carbon black, clay) that can be advantageously used in PLA/GTR blends. Indeed, the use of the finest cryo-grinded GTR in the presence of DCP showed the least decrease of the tensile strength (−30%); maintenance of the tensile modulus and the largest improvement of the strain at break (+80%), energy at break (+60%) and impact strength (+90%) as compared to the neat PLA. The results were attributed to the good dispersion of both fine GTR and clay particles into the PLA matrix. Moreover, a possible re-crosslinking of the GTR particles and/or co-crosslinking at PLA/GTR interface in presence of DCP is expected to contribute to such improved ductility and impact strength.

Rational design for enhancing mechanical and conductive properties of Ti3C2 MXene based elastomer composites

Herein, we propose a novel Ti3C2 grafted SiO2 (Ti3C2-g-SiO2, 21.2% loading weight content of SiO2) multifunctional filler with an average thickness of 10 ± 2 nm, which is skillfully prepared via an in-situ growing approach, to blend with styrene-butadiene rubber (SBR) and create high-performance elastomer composites. Thanks to the incorporation of SiO2, the Ti3C2-g-SiO2 not only disperses better (a uniform state) than Ti3C2 in the rubber matrix but also obtains innumerous nano protuberances on its surface to constrain more rubber chains than Ti3C2, significantly improving the interfacial interaction. Therefore, by comparison of the unfilled SBR sample, the mechanical strengths of the prepared Ti3C2-g-SiO2 filled SBR sample are dramatically enhanced, including tensile strength (enhanced by 244%, from 4.09 to 14.1 MPa) and elongation at break (enhanced by 93%, from 271 to 522%). More importantly, the Ti3C2-g-SiO2 filled SBR sample featuring excellent electrical (8.96 × 10−4 S m−1) and thermal conductivities (0.449 W m−1 k−1), which could exceed the reduced graphene oxide filled SBR sample.

Enabling Superior Thermo-Oxidative Resistance Elastomers Based on a Structure Recovery Strategy.

Thermo-oxidative process leads to the structure damage of elastomers, such as the scission of main chains and destruction of crosslinks. The problem that damaged structure brings about the deterioration of mechanical properties has not been solved by the conventional anti-aging methods. Inspired by self-healing process, a structure recovery strategy for recovering the damaged structure induced by thermo-oxidative process is proposed, which endows elastomers with superior thermo-oxidative resistance. The high reactivity between 1,3-diisopropenylbenzene and free radicals realizes high recovery efficiency (from 83% to 118%); the changes in topology structure during recovery process make much more rubber chains bear external stress and improve mechanical properties significantly (from 18.5 to 29.6MPa). This work paves the way for the development of elastomers with superior thermo-oxidative resistance, meanwhile this work is helpful to push the theoretical research of self-healing to practical application.

Design and fabrication of mechanically strong and self-healing rubbers via metal-ligand coordination bonds as dynamic crosslinks

Developing mechanically strong and efficient self-healing rubbers is booming and shows great potential in a wide range of applications. Herein, by introducing pyridine ligands onto rubber chains via ring-opening reaction between epoxy groups and aminopyridine, we constructed dynamic Fe3+-pyridine coordination bonds in commercially available epoxidized natural rubber (ENR). The reversible nature of the coordination bonds endows the rubbers with efficient self-healing behavior under moderate conditions. Meanwhile, the coordination bonds can also serve as crosslinking points, which enhanced mechanical properties of the fabricated rubbers. When the molar ratio of Fe3+ to pyridine was 1 : 4, the tensile strength and 100% modulus reached 2.23 and 0.78 MPa, which are 18-times and 8-times that of the neat sample. Noteworthy, the sample also shows excellent self-healing capability with healing efficiency of 87% (tensile strength). Furthermore, by embedding conductive materials, we designed a conductive rubber with sandwich structure, which exhibits sensitive strain sensing behavior in detecting small strains.

Influence of Treated Distillate Aromatic Extract (TDAE) Content and Addition Time on Rubber-Filler Interactions in Silica Filled SBR/BR Blends.

High compatibility and good rubber–filler interactions are required in order to obtain high quality products. Rubber–filler and filler–filler interactions can be influenced by various material factors, such as the presence of processing aids. Although different processing aids, especially the plasticizers, and their effects on compatibility have been investigated in the literature, their influence on rubber–filler interactions in highly active filler reinforced mixtures is not explicit and has not been investigated in depth. For this purpose, the influence of treated distillate aromatic extract (TDAE) oil content and its addition time on interactions between silica and rubber chains were investigated in this study. Rubber–filler and filler–filler interactions of uncured and cured silica-filled SBR/BR blends were characterized by using rubber layer L concept and dynamic mechanical analysis, whereas mechanical properties were studied by tensile test and Shore A hardness. Five parts per hundred rubber (phr) TDAE addition at 0, 1.5, and 3 min of mixing were characterized to investigate the influence of TDAE addition time on rubber–filler interactions. It was observed that addition time of TDAE can influence the development of bounded rubber structure and the interfacial interactions, especially at short time of mixing, less than 5 min. Oil addition with silica at 1.5 min of mixing resulted in fast rubber layer development and a small reduction in storage shear modulus of uncured blends. The influence of oil content on rubber–filler and filler–filler interactions were investigated for the binary blends without oil, with 5 and 20 phr TDAE content. The addition of 5 phr oil resulted in a slight increase in rubber layer and 0.05 MPa reduction in Payne effect of uncured blends. The storage tensile modulus of vulcanizates at small strains decreased from 13.97 to 8.28 MPa after oil addition. Twenty parts per hundred rubber (phr) oil addition to binary blends caused rubber layer L to decrease from 0.45 to 0.42. The storage tensile modulus of the vulcanizates and its reduction with higher amplitudes were incontrovertibly high among the vulcanizates with lower oil content, which were 13.57 and 4.49 MPa, respectively. When any consequential change in mechanical properties of styrene–butadiene rubber (SBR)/butadiene rubber (BR) blends could not be observed at different TDAE addition time, increasing amount of oil in blends enhanced elongation at break, and decreased Shore A hardness and tensile strength.

Effects of coagent incorporation on properties of ultrafine fully vulcanized powdered natural rubber prepared as toughening filler in polybenzoxazine

AbstractUltrafine fully vulcanized powdered natural rubber (UFPNR) is a renewable material that is promising for industrial application as a toughening filler in polymer matrix. In this work, effects of coagent on properties of UFPNR produced by radiation vulcanization and spray‐drying was systematically investigated, in which trimethylol propane trimethaacrylate (TMPTMA) was used as coagent. The crosslinking density of UFPNR could be enhanced by increasing radiation dose from 50 to 350 kGy and it was further enhanced by using TMPTMA as coagent during the production process. UFPNR with the smallest particle size of 3.9 ± 1.8 μm and highest thermal stability (Td5 = 347°C) could be obtained by using TMPTMA with the highest content of 9 phr. The results suggested that polymer chains of natural rubber were more packed into smaller particle as they were more crosslinked by the coagent. Finally, an application of UFPNR as a toughening filler in polybenzoxazine was demonstrated. The highest impact strength improvement of 20% was achieved by incorporation of 3 phr UFPNR in polybenzoxazine.

A high-performance, thermal and electrical conductive elastomer composite based on Ti3C2 MXene

In this study, a single-layered Ti3C2 hybrid SiO2 filler (Ti3C2-h-SiO2) was proposed to fabricate high-performance styrene-butadiene rubber (SBR) elastomer composites. It was found that incorporating SiO2 not only facilitated the uniform dispersion of Ti3C2-h-SiO2 in the SBR matrix but also endowed the surface of Ti3C2-h-SiO2 with nano protuberances for immobilizing more rubber chains, resulting in the improvement of the interfacial interaction between Ti3C2-h-SiO2 and SBR matrix. Thus, the tensile strength of the SBR/Ti3C2-h-SiO2 elastomer composite was reinforced by 174% compared with the unfilled SBR. Moreover, the wet skid resistance and rolling resistance of the SBR/Ti3C2-h-SiO2 elastomer composite were also remarkably improved. Noteworthily, the exceptional thermal conductivity (0.401 W m−1 k−1) and electrical conductivity (4.87 × 10−4 S m−1) of the SBR/Ti3C2-h-SiO2 elastomer composite were comparable to the SBR/reduced graphene oxide (rGO) elastomer composite, implying that the conductivity of Ti3C2-h-SiO2 may be competitive with the rGO.

High-Temperature-Aging Induced Sequential Recovery of Shape Memory Nitrile Butadiene Rubber Composites.

The sacrificial bonds in natural materials have inspired the preparation of shape memory polymer (SMP), which can be prepared through the construction of dual cross-linking networks in a polymer matrix. With the rise of 4D printing technology, fine control over the shape recovery of SMPs, especially control over the recovery time, is urgently needed. In this study, the high-temperature aging method is adopted to tune the shape recovery time of dual cross-linked SMPs. Shape memory acrylonitrile butadiene rubber composite (i.e., NBR-C) is prepared by introducing Zn2+-C≡N coordination bonding and sulfur covalent cross-linking networks into the rubber matrix and then thermal aging at 180 °C for various time frames. Aging increases the covalent cross-linking density, ruptures rubber chains, and generates imine structures. Moreover, the composition of the coordination bonding network becomes diversified because of the formation of coordination bonds between imines and Zn2+ ions. The mechanical "tough-brittle" transition of aged NBR-C is observed, and its glassy temperature increases with aging time, which in turn changes the shape recovery time at the same recovery temperature. On the basis of these findings, the special shape memory rubber components with sequential recovery are fabricated by partially aging the NBR-C strings. This methodology provides novel solutions for the preparation of sequential SMP products without programming heating design or using redundant chemical materials. We believe that this work will be able to help promote comprehensive research of SMPs and widen applications of SMPs in the industry.

Effects of Substituting Polyisoprenyl Carbanions for Ethoxyl Groups of Bis-[3-(triethoxysilyl)propyl] Tetrasulfide on the Properties of Carbon Black and Silica-Reinforced NR/SSBR.

The coupling agent TESPT (bis-[3-(triethoxysilyl)propyl] tetrasulfide) was modified by substituting polyisoprenyl (PI) carbanions for the ethoxyl groups on silicon for increasing the interaction of rubber with its fillers. The modification was carried out by the reaction of TESPT with polyisoprenyllithium, which had been previously prepared by anionic polymerization of isoprene using butyllithium. The success of the substitution was confirmed by Fourier-transform infrared spectroscopy, and the molecular weight of the modified TESPT (PI-TESPT) was determined from gel permeation chromatography measurements. The effects of tethered PI, as well as of its chain length, on the mechanical and dynamic properties of rubber compounds were examined using a universal testing machine and dynamic mechanical analysis (DMA). In rubber sample preparation, the amount of PI3-TESPT (PI of 2900 g/mol) used in rubber compounding is equal to that of the reference sample with TESPT (STESPT). For SPI-TESPT samples, the amounts of PI6-TESPT (PI of 5500 g/mol) and PI14-TESPT (PI of 13,700 g/mol) used were calculated as molar ethoxyl groups which are nearly equivalent to those of PI3-TESPT. At the same wt % (parts per hundred, phr) of elemental sulfur in rubber compounds, despite the order of cross-linking density being STESPT (sample prepared with TESPT) > SPI3-TESPT > SPI6-TESPT > SPI14-TESPT, the exhibited tensile strength is of the order of SPI3-TESPT > SPI6-TESPT > STESPT ≈ SPI14-TESPT. The better mechanical properties of SPI3-TESPT, as opposed to those of STESPT, could be attributed to the extra reinforcement from the PI–rubber chain linkage and better silica dispersion, as suggested by the mixing torque and Payne effect (ΔG′) measurements. While the dynamic properties of SPI3-TESPT are inferior to those of STESPT, these properties can be improved by adding more elemental sulfur to increase the cross-linking density.

Reaction mechanism and rheological properties of waste cooking oil pre-desulfurized crumb tire rubber/SBS composite modified asphalt

Waste cooking oil (WCO) is proved to be effective in desulfurization of crumb tire rubber (CTR), which can be considered as a sustainable desulfurization technology and an alternative way to solve the poor storage stability of asphalt rubber. However, WCO pre-desulfurized CTR (ODR) modified asphalt displays a compromised high-temperature performance, leading to a limited application of ODR in asphalt modification. In this study, ODR/styrene–butadiene-styrene (SBS) composite modified asphalt was developed to make up the loss of high-temperature performance. The reaction mechanism of ODR/SBS composite modified asphalts with and without sulfur was investigated via Fourier transform infrared spectroscopy (FTIR), gel permeation chromatograph (GPC) and fluorescence microscope (FM). Rheological tests were conducted to clarify the effects of ODR, SBS and sulfur on the rheological behavior of the modified asphalt. FTIR, GPC and FM results proved that crosslinking reaction occurred during the composite modification of ODR, SBS copolymer and base asphalt in the presence of sulfur with moderate content, forming a continuous and homogeneous microstructure with a significantly increased large molecular weight, which is less prone to produce phase segregation. The ODR composite modified asphalt with 3 wt% SBS and 0.4 wt% sulfur presents the best rutting resistance due to the increase of the elastic network structure and cracking resistance due to the presence of WCO and the released rubber chain. The above composite modified asphalt meets the standard traffic level at 76 °C and the specification at −34 according to the multiple stress creep recovery and bending beam rheometer tests.

Visualization of chemical bonding in a silica-filled rubber nanocomposite using STEM-EELS

In nanocomposites, the adhesion between nanofillers and the polymeric matrix is key to the mechanical properties. The strength and spatial distribution of the adhesive layer around the nanofillers are important, particularly the presence of chemical bonding between the nanofillers and matrix. In this work, we studied a styrene-butadiene rubber composite filled with silica nanoparticles to visualize the spatial distribution of the adhesive layer. A silane coupling agent (SCA) was added to the nanocomposite for strong adhesion. The reaction involving the SCA on the silica surface was investigated by scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Si-L2,3 spectra of the silica-filled rubber nanocomposite without the SCA were the same around the nanofillers, whereas in the nanocomposite containing the SCA the spectra were position-dependent. The spectra were fitted with the intensity profiles of the Si-L2,3 spectra of silica and SCA by multiple linear least-squares fitting. The fitting coefficients of silica and SCA were used to map the spatial distribution of the chemical bonding between silica and rubber chains. Chemical bonding was observed around the silica nanoparticles but not in the SBR matrix region, providing direct evidence of the reinforcing mechanism in the silica-filled rubber nanocomposite.

HbWRKY27, a group IIe WRKY transcription factor, positively regulates HbFPS1 expression in Hevea brasiliensis

Farnesyl pyrophosphate synthase (FPS) is a key enzyme that catalyzes the formation of farnesyl pyrophosphate, the main initiator for rubber chain initiation in Hevea brasiliensis Muell. Arg. The transcriptional regulatory mechanisms of the FPS gene still not well understood. Here, a WRKY transcription factor designated HbWRKY27 was obtained by screening the latex cDNA library applied the HbFPS1 promoter as bait. HbWRKY27 interacted with the HbFPS1 promoter was further identified by individual Y1H and EMSA assays. HbWRKY27 belongs to group IIe WRKY subfamily which contains a typical WRKY domain and C-X5-CX23-HXH motif. HbWRKY27 was localized to the nucleus. HbWRKY27 predominantly accumulated in latex. HbWRKY27 was up-regulated in latex by ethrel, salicylic acid, abscisic acid, and methyl jasmonate treatment. Transient expression of HbWRKY27 led to increasing the activity of the HbFPS1 promoter in tobacco plant, suggesting that HbWRKY27 positively regulates the HbFPS1 expression. Taken together, an upstream transcription factor of the key natural rubber biosynthesis gene HbFPS1 was identified and this study will provide novel transcriptional regulatory mechanisms of the FPS gene in Hevea brasiliensis.

Influence of SiC and TiO2 on the cure characteristics and mechanical properties of natural rubber composites

Natural rubber composites were prepared using silicon carbide and titanium dioxide as filler in different proportions. Curing characteristics were investigated as a function of filler loading and filler proportion. Mechanical properties like tensile strength, tear strength, hardness, elongation at break and modulus were determined. Both tensile strength and modulus were found to increase with SiC (Silicon carbide) content which may be due to the restrictions offered by filler particles to the rubber chain mobility. Cure properties also support the reinforcing capacity of SiC filler in the natural rubber matrix.

Experimental and computational study on chloride ion transport and corrosion inhibition mechanism of rubber concrete

Rubber concrete is an innovative environmentally-friendly building material in which waste rubber is recycled as a concrete component. Durability research of rubber concrete is an important prerequisite for its applications in marine and coastal engineering. The low-permeability and cracking-resistance characteristics of rubber demonstrate its potential to delay chloride ion penetration and corrosion-induced cracking from the perspective of material properties. However, the microstructural characteristics of rubber concrete are extremely complex, leading to uncertainties in transport process and corrosion evolution in this material. In order to promote the utilization of waste rubber in concrete and to improve durability of infrastructure in the marine environment, the chloride ion transport characteristics and corrosion inhibition mechanism of rubber concrete are systematically studied in this paper from the aspects of macroscopic experiments and microscopic simulations. In macroscopic experiments, a novel corrosion evaluation technique of rubber concrete is proposed using electrically accelerated methods and nondestructive ultrasonic testing. The experimental results show that the addition of waste rubber can effectively reduce the chloride ion diffusion coefficient, inhibit the steel corrosion and improve the durability of concrete structures. Further, in microscopic simulations, a transport model is established based on molecular dynamics to simulate the erosion of sodium chloride solution in ideal cement and rubber nanopores, revealing the transport mechanism of chloride ions in rubber concrete. The molecular dynamics simulations indicate that sodium ions and chloride ions are confined in rubber chains during the transport process, instead of forming chemical bonds at the rubber surface.

Flammability, thermal stability, and mechanical properties of ethylene‐propylene‐diene monomer/polypropylene composites filled with intumescent flame retardant and inorganic synergists

AbstractThree kinds of inorganic particles, zinc borate (ZB), organic montmorillonite (OMMT), and expanded graphite (EG) as synergistic flame retardants, are incorporated into ethylene‐propylene‐diene monomer/polypropylene (EPDM/PP) composites filled with intumescent flame retardants (IFR). The effect of three synergistic flame retardants on the combustion, thermal stability, and mechanical properties of the EPDM/PP/IFR composites are investigated by limiting oxygen index (LOI), UL‐94 test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy, mechanical property testing, and dynamic mechanical analysis (DMA). The results from LOI, UL‐94, and CCT show that the synergistic effect of IFR with ZB and EG is better than IFR with OMMT in the flame retardant EPDM/PP/IFR composites. The TGA results indicate that the thermal stability and char residues of the composites is improved with the addition of inorganic particles, which is attributed to the formation of dense char layers to isolate heat flow. DMA results including storage modulus (G'), loss modulus (G"), and loss factor (tan δ) suggest that the composites with inorganic particles exhibit more rubber‐filler interaction, which limits the movement of the rubber chains.

Adhesion enhancement between aluminum and butyl rubber by (3-mercaptopropyl) trimethoxy silane for vibration damping plate

A silane coupling agent for an aluminum-based vibrational damping plate with a butyl rubber damper, which shows excellent viscoelasticity and thermal stability, was studied to enhance the adhesion strength between aluminum and butyl rubber. Considering the chemical structure of the butyl rubber, we introduced (3-mercaptopropyl) trimethoxysilane (MPTMS) as the silane coupling agent because it has a thiol functional group that can bind to the carbon chain of butyl rubber via thiol-ene reaction under heating. Based on the results of various surface analyses and the T-peel strength test, the MPTMS treatment condition was optimized, and a 180% enhancement of peel strength was obtained. Finally, a central supporting vibration test was conducted to prove the damping performance of aluminum damping plated with MPTMS. As a result, a 7-fold enhancement in the damping loss factor was seen in the damping with MPTMS compared to without.

Analysis of diffusion characteristics for aromatic solvents through carbon black filled natural rubber/ butadiene rubber blends

AbstractKnowledge of solvent effect on the polymer is a need, for a large number of industrial and laboratory purposes. It is well known that swelling is a serious drawback for rubber products such as seals and O‐rings. The flexible rubber chains are highly prone to diffusion and allow easy penetration of solvent molecules through it, which causes swelling in rubber products. The flexibility and molecular mobility of rubber chains are reduced by either cross‐linking/blending/ adding inclusions. This reduces the swelling of rubber products. In the present work, blending rubbers and adding inclusions are experimented and reported. Various compositions of natural rubber (NR) / butadiene rubber (BR) i.e., 70NR/30BR, 50NR/50BR,30NR/70BR with and without carbon black (CB) were compounded, cured and characterized for diffusion analysis using benzene, toluene, and xylene. To determine the effect of varying filler concentration, 70NR/30BR blend was filled with 10, 20, 30, 40, and 50phr of CB and analyzed for diffusion characteristics. Loading of CB into rubbers reduces the chain flexibility as a result of rubber/filler interactions and this leads to a dramatic reduction in the diffusion of the solvent into rubber compounds. Diffusion characteristics of CB filled rubber blends were compared with their neat counterparts and CB filled blends showed less solvent uptake. Swelling characteristics for the neat and filled rubbers and their blends were calculated to determine coefficients and index of swelling. The experimental diffusion data obtained were fitted with mathematical models for predicting the diffusion behavior through the rubber vulcanisates to understand the mechanism of transport phenomena.

Effect of protein on the thermogenesis performance of natural rubber matrix

Under high-speed strain, the thermogenesis performance of natural rubber products is unstable, leading to aging and early failure of the material. The quality of rubber latex and eventually that of the final products depends among others on the protein content. We found that when the protein is almost removed, the heat generated by the vulcanized rubber increases rapidly. After adding soy protein isolate to the secondary purification rubber, the heat generation of the vulcanized rubber is reduced, and the heat generation is the lowest when the added amount is 2.5–3.0 phr, which on account of protein promotes the construction of a vulcanization network and increases the rigidity of the rubber chain, resulting in a decrease in the potential frictional behavior of the rubber chain during the curl up-extension process.