Study On Pretreatment Of Aramid Nanofibers And Properties Of Its Filled Rubber

Most of the engineering tire tread rubber’s matrix are made by natural rubber,since the working conditions are totally harsh and mainly concentrated in the sites and mines where the tire wore seriously,it is necessary to strengthen the tread rubber.As a kind of good reinforcing filler,aramid nanofibers have excellent reinforcing effect because of its high specific surface area,which makes its bond with rubber higher than that of aramid short-cut fiber.However,the high specific surface area also leads to agglomeration easily.This study is mainly aimed at this problem and proposes a kind of method to prepare fine pre-dispersed aramid nanofibers masterbatch by ultrasonic crushing,surface modification and latex flocculation.And based on this method,we’ve made the aramid nanofibers dispersion masterbatch,sub-micron aramid pulp dispersion masterbatch,aramid nanofibers and sub-micron aramid pulp dispersion composite masterbatch respectively,then use these three kinds of masterbatch to reinforce engineering tire tread rubber whose matrix is the natural rubber and study the impacts on its properties.The results show that the modulus gain property of the sample treated with butadiene-vinylpyridine latex is better than that of natural latex,but the dispersion property is lower,what’s more,the pre-treated aramid nanofibers filled rubber shows lower T₉₀.When using epoxy resin-isocyanate and RFL immersion liquid system of modification,and employing natural latex flocculation with fiber filling amount of 1 phr,aramid nanofiber filled rubber can increase the 20%fixed elongation stress by 20%,the tear strength by 8%,the dynamic cutting resistance by18%,the wear resistance by 8%and the crack growth resistance by 33%at higher tear energy.The submicron aramid pulp filled rubber can increase the 20%fixed elongation stress by 63%,tear strength by 30%and dynamic cutting resistance by 33%.When the compound ratio of the aramid nanofiber and the submicron aramid pulp is 1:1,the filled rubber’s20%fixed extension stress,elongation at break,tear strength,dynamic cutting resistance and crack propagation performance are increased by30%,44.5%,20%,22%and 21%,respectively.