Research On The Mechanical Property Of Short Aramid Fiber Reinforced Styrene Butadienerubber Composite

In this paper,a kind of high performance engineering tire tread rubber,aramid fiber(AF)reinforced butadiene styrene rubber(SBR)composite,was prepared using a method of master batch.The research was focused on the following three aspects:(a)surface modification of the aramid fiber and the performances of the AF/SBR composites;(b)the preparation of the compatilizer,hydroxyl-terminated polybutadiene grafted maleic anhydride(HTPB-g-MA)and its application in the AF/SBR composites;(c)the influence of dosages and mass ratios of AF and the prepared compatilizer on the performances of AF/SBR composites.The performances of the AF/SBR composites such as mechanical properties,dynamic properties,interfacial properties and cutting resistances were investigated by mechanical test,DMA,SEM,FTIR,RPA and dynamic cutting test.The results are described as follow:(1)Influences of complexing modification methods of AF on the performances of AF/SBR composites were discussed.The results indicated that the mechanical properties and interface adhesion of AF/SBR composites were improved when AF was modified by Li Cl or Ca Cl₂,with the AF modified by Li Cl being the better.(2)Influences of oxidative thermal treatment conditions on the performances of AF/SBR composites were investigated.The results showed that the stress at definite elongation and dynamic mechanical properties of AF/SBR composites could reach a best value when AF had been treated for 3 min at 200?.Moreover,the properties of AF/SBR composites could apparently improved after an oxidative thermal treatment of AF compared with the untreated one.(3)Impacts of the pre-coated compatibilizer of AF on the performances of AF/SBR composites were studied.The findings showed that the pre-coated compatibilizer of AF could enhance the tensile stress at 100%and tensile stress at 300%of the AF/SBR composites efficiently,and the better performance of AF/SBR composites could be obtained when the pre-coated fibers had been placed at room temperature for 24h.From the results of SEM,DMA and RPA test analysis,it was founded that the interface bonding performance,wear-resisting property and dynamic mechanical performance of the composite were the best.(4)The effects of fabricating methods of HTPB-g-MA on the AF/SBR composite properties were researched,and the orthogonal experiment results showed that the fabricating temperature was the most obvious impact factor for the mechanical properties of AF/SBR composite.The best property of HTPB-g-MA could be obtained when the system contained 0.35 phr BPO,4 phr MA,8 phr epoxy(EP)and reacted for 0.5 h at 120?.The FT-IR results indicated MA and EP were successfully grafted onto the main chain of HTPB,and the esters were formed.(5)The influences of mass ratio between HTPB-g-MA and AF on the performances of AF/SBR composites were discussed.The results showed that the tensile stress at 100%and tensile stress at 300%of AF/SBR composites with any mass ratio between HTPB-g-MA and AF improved with the increasing of the AF dosage.Tearing strength,dynamic cutting performance and dynamic mechanical properties of AF/SBR composites reached a best value when the AF dosage was 4phr and the mass ratio between HTPB-g-MA and AF was 1:1.The SEM results revealed that HTPB-g-MA could efficiently improve the interfacial bond property of the AF/SBR composites.RPA analysis showed an increase of storage modulus and loss modulus,and a decrease of tan?,with the increasing AF dosage,which indicated an improved dynamic mechanical property.However,an opposite result would be observed when the dosage of HTPB-g-MA was excess.The bestdynamic mechanical property of AF/SBR composite could be achieved when the mass ratio between HTPB-g-MA and AF was 1:2.