Study On Modified Pre-dispersion Treatment Of Superfine Aramid Short Fiber And Its Filled Rubber

Aramid pulp is a short fiber product obtained by fibrillating aramid fibers.There are a large number of ultra-fine aramid short fibers around the main fibers,which-have a high specific surface area.However,compared with untreated aramid chopped fiber,the interface bonding point between aramid pulp and rubber matrix is better than aramid chopped fiber,and the reinforcement effect is better.This study is mainly aimed at the problems of easy agglomeration of aramid pulp and poor binding with the rubber matrix.We have studied the effects and reinforcement mechanisms of aramid pulp reinforcement on EPDM,NR,MVQ.By improving the dispersibility and interfacial bonding properties,we propose specific modification and pretreatment processes for the respective ultrafine aramid short fibers.The research on the conveyor belt covering rubber filled with EPDM rubber as the matrix was carried out.We use coupling agent and liquid isolation agent to modify and pre-disperse the aramid pulp to prepare APM-E40 masterbatch,which effectively improves the dispersion performance and interface bonding performance of aramid pulp.At the same time,we find the shape of the fiber has a certain influence on the performance of the rubber compound.The higher the length-diameter ratio and the larger the specific surface area of the fiber,the more obvious the effect of reinforcing the rubber,and the better the performance of the reinforcing rubber material.The amount of APM-E40 has a greater impact on the fiber-filled conveyor belt covering rubber.The increase in the amount of fiber will cause the tensile strength of the compound to decrease,the fixed tensile stress,modulus,the hardness of the compound,tear resistance and dynamic cutting resistance will increase significantly.In combination with the decrease of the tensile strength and the improvement of other properties,the amount of pure fiber of aramid pulp is more suitable when it is 3Phr.It can improve the tear strength by about 33%,the 20%constant extension stress by about 150%,and the dynamic cutting resistance by about 13%of the conveyor belt cover rubber.The research on engineering tire tread rubber filled with aramid pulp filled with natural rubber as the matrix was carried out.We modified and pre-dispersed the aramid pulp and filled it into the engineering tire tread compound added with resorcinol formaldehyde bonding system.Based on its various properties,3Phr blocked poly diisocyanate and 1Phr epoxy resin were used for surface modification when modifying and pre-dispersing aramid pulp,and LIR was used as liquid separator to prepare APM-N431.At the same time,a resorcinol formaldehyde resin bonding system should be added to the rubber compound to further improve the bonding.The suitable dosage of APM-N431 reinforced engineering tire tread rubber is 1.5Phr of pure fiber.It can improve the engineering tire tread rubber M20 by about 140%,the crack propagation resistance by about 10%,and the dynamic cutting resistance of the fiber orientation along the axial direction by about 30%,but it will cause a drop of about 5%in its tensile strength.When the aramid pulp is used to improve the dynamic cutting resistance,the dynamic cutting resistance is more obvious when the fiber is oriented in the axial direction compared to the cutting direction in which the fiber is oriented in the circumferential direction.The aramid pulp reinforced methyl vinyl silicone rubber material was also studied.APM-Q431 prepared by surface modification of aramid pulp with blocked polydiisocyanate and epoxy resin and vinyl silicone oil as a separator for permeation and isolation.It has a good effect on the reinforcement of methyl vinyl silicone rubber.With the increase of the amount of aramid pulp,the tensile strength of the vulcanized rubber is slightly reduced,and the constant tensile stress,modulus,tear strength and hardness of the vulcanized rubber are continuously improved.Comprehensive performance of the compound,when using aramid pulp to reinforce methyl vinyl silicone rubber,it is more appropriate to add APM-Q431 with a pure fiber amount of 1.5Phr to the compound,which can improve the M20 of the compound About 287%,tear strength is about 51%,at the same time can also increase the tan δ at 60℃ to a certain extent.