Hybrid Modified Waste Rubber Powder And Its Application In Rubber

Waste rubber powder (RP) is obtained by mechanical crushing and grinding ofvulcanized waste rubber. Thus, it is a kind of rubber with inorganic filler and curing agentadditive composition with cross linked structure. With economic development, social andeconomic activities generate lots of waste rubber. The exist of waste rubber not only wastesland resources, does harm to the environment and leads to the security risks, but also misleadslot of resources into synthetic rubber, which doesn’t live up to sustainable development ofhuman society. Making rubber powder(RP) from waste rubber and using it in rubber andplastics can help costs reducing and waste rubber recycling. However, the RP’s surface has alow chemical reactivity, with only a small number of chemical group. Therefore, if thepowder material is applied directly to the polymer, poor compatibility with the matrixmaterial, the composite material tends to result in reduced performance. So for theexpanding use of RP, increasing usage amount of RP and thus improving its economic value,modification of RP is needed.Previously, our group studied sol-gel modified RP (prepared the modified nano-silicahybrid powder) and applied it to natural rubber. Result showed the modified RP significantlyenhanced the interfacial interactions between natural rubber and RP, improved heat resistanceand mechanical properties especially significantly improved tensile properties and reduced themodified powder/natural rubber matrix composite wear.Based on the previous work, this paper studied the hybrid modified NRPs which wereprepared by sol-gel method with sodium silicate as a precursor and the two hybrid modifiedVRP and PIRP the surface of which grafted with reactive functional groups. The two hybridmodified VRP and PIRP were grafted with vinyl and carboxyl functional groupsaminothioxomethyl respectively. Their structure and properties were characterized by FTIR,TGA and other analytical techniques.CPE rubber is a kind of saturated rubber with excellent overall performance and heatoxygen ozone aging advantages, but it is expensive and poor at tear strength, which limitCPE to large-scale application. So we studied the addition of VRP with double bonds in CPEto learn the effect of structure and properties of the blends. Compared with RP, the hybridmodified VRP had better physical crosslinking and bonding interaction between the VRP andCPE interface. Therefore VRP significantly improved the mechanical properties and agingproperties of CPE, especially tearing properties. Compared to pure CPE, CPE compositesadding30phrVRP increases15%on tearing properties, the aging factor decreased from0.34 to0.09. And further study found that adding Mg(MMA)2enhanced the CPE/VRP blends.Mg(MMA)2in the CPE vulcanization process not only leaded to bulk polymerization, but alsobrought graft reaction with CPE molecular chain. And Mg(MMA)2generated C-C bond withthe vinyl belonging to VRP, which made the network structure of CPE blends more perfectand thus helped to improve blends performance.Styrene butadiene rubber(SBR) is a kind of general rubber, widely applied in tires, belts,hoses, wires and cables, medical equipment and so on. The adding of PIRP modified withamino thiocarboxy in SBR rubber composites was studied to learn the effects of structural andperformance of blends. The results showed that, PIRP and CZ vulcanization accelerator usedtogether played a synergistic role in SBR rubber vulcanizing, greatly reduced the time andtemperature required for SBR vulcanization. Adding30phr PIRP to SBR, the vulcanizationtemperature was decreased to130℃, curing time was decreased from68min to23min,thereby greatly reducing the energy consumption of the vulcanization reaction. By furtherprocessing performance, swelling behavior, thermal properties, dynamic mechanicalproperties, morphology characterization tests and observation found the addion of PIRPincreased the cross-linking density of the blends and glass transition temperature. Thatindicated PIRP was lipophilic and PIRP after decomposition of the thio amino thiocarboxybelonging to PIRP during curing improved the molecular chain entanglement between SBRand PIRP of the two-phase interface and enhanced two-phase interfacial strength to improvethe mechanical properties of the blends. Compared with the tensile strength of pure SBRrubber, the tensile strength of SBR/PIRP-30increased by135%, the tear strength increasd by87.4%.