Surface Modification Of Wet Method Rubber Powder And Study On Its Application

The rapid development of the automobile industry has resulted in a sharp increase in the use of vehicles,bringing about large quantities of waste tires.The environmental pollution and waste of resources caused by these tires have attracted much attention.Therefore,the recycling of waste tires has become increasingly important.Producing rubber powder by wet method is an economic,environmentally friendly and effective way of recycling.The rubber powder was applied to other matrix materials,and the interfacial binding force of the two was improved by modifying rubber powder,which has certain practical application and economic value.Firstlt,the physical and chemical properties of rubber powders and asphalt were characterized and analyzed.Scanning electron microscope(SEM)showed that the surface roughness of rubber powder by wet method was higher than that of rubber powder by dry method.The 80 mesh rubber powder(wet method)contained some carbon-carbon double bonds,which provided the feasibility for rubber powder modification.There were many hydrophobic alkyl segments in asphalt,which also contanined hydrophilic hydroxyl(-OH).Secondly,sulfuric acid was used to activate rubber powder(wet method),and then the coupling agent CTS was used to graft the accelerator M onto the surface of the rubber powder to obtain the grafted rubber powder with a vulcanization promotion function,which was used for the blending modification of styrene-butadiene rubber.The unmodified waste rubber powder(GTR),sulfuric acid activated rubber powder(S-GTR),coupling agent treated rubber powder(C-GTR),and accelerator M modified rubber powder(M-GTR)were characterized to analyze the modification mechanism.FTIR,XPS,TG and water contact angle proved that the accelerator M was grafted onto the surface of the rubber powder,and the grafting rate was 3.1%.SBR,SBR/GTR,SBR/C-GTR,and SBR/M-GTR were tested and characterized.From the vulcanization curve,SBR/M-GTR possessed the shortest scorch time and vulcanization time,which meant the fastest vulcanization rate,indicating M-GTR could promote the vulcanization of the styrene-butadiene rubber / rubber powder composite.The swelling experiment calculated that SBR/M-GTR exhibited the largest crosslink density among filled SBR.SBR/M-GTR showed the highest tensile strength,which was 137.4% and 85.1% higher than that of the unfilled SBR and SBR/GTR,respectively.According to DSC analysis,SBR/M-GTR demonstrated the highest restricted molecular layer mass fraction(?im),suggesting the strongest interface interaction in SBR/M-GTR.Thirdly,the comprehensive road performances of rubber asphalts,prepared by 40 mesh,60 mesh,80 mesh and 100 mesh rubber powder,were compared.100 mesh rubber powder(wet method)showed the best performance.Hydrogen peroxide were utilized to modify rubber powder,and sodium tungstate was used to catalyze the rubber powder to epoxidize to enhance the interaction between rubber powder and saphalt.The rubber asphalt prepared by blending the hydrogen peroxide modified rubber powder and asphalt showed higher softing point,increased ductility and lower penetration than that of rubber asphalt prepared by unmodified rubber powder.However,the viscosity dropped to less than 1000 Pa·s.The rubber asphalt prepared by hydrogen peroxide modified rubber powder catalyzed by sodium tungstate had an increase in viscosity in the range of 1000-2000 Pa·s,which was at the optimal level.1.5 portion of sodium tungstate catalyzed hydrogen peroxide modified rubber powder modified asphalt exhibited the best comprehensive performance.Five amphiphilic compound were utilized to modify rubber asphalt.Overeall,comprehensive road performance of amphiphilic compound modified rubber asphalt were improved.The rubber asphalt modified by ?-cyclodextrin exhibited the best comprehensive road performance.Hydrogen peroxide treated rubber powder and ?-cyclodextrin modified asphalt could be improved to the the best level on viscosity.Hydrogen peroxide modified rubber powder/?-cyclodextrin /asphalt had the best comprehensive road performance compared to hydrogen peroxide modified rubber powder/asphalt and unmofified rubber powder/asphalt.Interaction mechanism between ?-cyclodextrin and hydrogen peroxide modified rubber powder and asphalt was investigated via FTIR,TG,XPS,DSC and SEM.It was found there were physical and chemical blending mechanism.