Preparation Of Novel Multifunctional Biomass Rubber Antioxidant And Its Influence On The Structure And Properties Of Rubber Composite

Based on the current development requirement of"green tire",we have utilized biomass compounds such as tea polyphenols(TP)and theobromine(TB)with excellent free radical scavenging and antioxidant activity to prepare supported biomass rubber antioxidant silica-s-TP through"one-step"method surface chemical decoration,and HNTs-s-TP with slow release effect through vacuum pumping and surface decoration.Moreover,the supported biomass rubber antioxidant G-TB has been prepared by surface chemical modification of nucleophilic reaction through TB and graphene oxide(GO).The thermal oxygen aging resistance,physical and mechanical properties,mobility and volatilization resistance and the prediction of thermal aging life of the composites were systematically studied.The main contents are as follows:(1)Several novel multifunctional biomass rubber antioxidants were prepared by the high efficiency,safety and environmentally friendly"one-step"method,which via the chemical reaction between the silicon hydroxyl on silica surface and tea polyphenols under catalysis.The structure and composition of silica-s-TP and the loading content of TP were systematically studied,in addition,the effects of different loading content of TP on the properties of styrene-butadiene rubber(SBR)composites were studied.The results shown that compared with the unloaded system,the supported antioxidant silica-s-TP system had excellent properties of migration resistance and volatility resistance.Moreover,adding silica-s-TP in SBR matrix could not only improve the dispersion of filler in SBR matrix,but also improve the mechanical properties of SBR/silica-s-TP composite.Through the study of the properties of SBR composites with the equal TP contents,the SBR/silica-s-TP-3 composites with high TP loading content possessed the most excellent properties.With the increase of TP loading content,the dispersion effect of silica-s-TP in rubber matrix was gradually improved,and the vulcanization degree,crosslinking density and the physical mechanical properties were obviously improved also.(2)As the previous study shown that,the SBR composite exhibited the most excellent comprehensive properties when the supported TP content up to 7%.Therefore,this study compared silica-s-TP of optimal loading rate with the commonly used antioxidants in rubber industry such as 4020,RD,2246 and 264.And systematically studies their thermal oxygen aging resistance properties in rubber matrix.Moreover,silica-s-TP had good thermal stability which could effectively improve the thermal aging properties of SBR composites.Under the same failure temperature,SBR/silica-s-TP composite shown the great long-lasting thermal aging life.Meanwhile,the anti-thermal oxygen aging mechanism of silica-s-TP in SBR matrix was in-depth studied.Through supported TP on silica surface,the heat resistance of silica-s-TP was improved.And the hydrogen bonds between rubber molecular chain were produced which leaded to the improving of interfacial interaction between rubber matrix.Furthermore,because silica-s-TP could effectively capture the free radical R·and ROO·produced during thermal oxygen aging,the autocatalytic reaction of rubber molecular chain could be effectively inhibited as well,which was beneficial to slow down the fracture of rubber molecular chains under thermal oxygen conditions,in addition improving the thermal oxygen aging resistance of rubber composites.(3)HNTs-s-TP with slow release effect was prepared by"two-steps"method,vacuum pumping and surface modification of halloysite nanotubes(HNTs)with TP,and applied to natural rubber(NR)to compared with the traditional antioxidant.The property of anti-thermal oxygen aging and anti-thermal aging life of NR/HNTs-s-TP composite were studied.The results shown that the modified Loaded HNTs with TP could effectively reduce the release rate of TP in the nanotubes,prolong the anti-thermal aging time and improve the thermal oxygen aging resistance of the composite.(4)By using the environmental-friendly and cost-effective biomass compound theobromine(TB)as a nucleophilic reagent,a novel multifunctional biomass rubber antioxidant G-TB was prepared by"one-step"method of S_N2 nucleophilic reaction between GO and TB.The preparation method had the advantages of simple process,lower price,non-toxic,environmental-friendly and mass-production.The results shown that G-TB could effectively improve the mechanical properties of NR/G-TB composite,improve the migration and volatile resistance of rubber additives,and also effectively improve the"blooming"phenomenon on the surface of rubber composites.Studies on the thermal oxygen aging resistance of NR/G-TB composite shown that the-NH group of G-TB could effectively capture,stabilize and scavenge the active free radicals produced during the thermal oxygen aging reaction,furthermore to inhibit and delay the aging process of NR/G-TB composite.Compared with the traditional antioxidants,the anti-aging effect of G-TB was better than that of phenolic antioxidant but a little poor than that of antioxidant RD.