Study On The Surface Modification And Properties Of Aramid Fiber

Aramid fiber has excellent properties such as high strength,high modulus,good heat resistance and low density.Aramid products have been widely used.At present,the composite of aramid fiber reinforced still faces some problems,it is mainly because of the higher crystallinity of aramid fiber and the steric hindrance of the benzene ring,which makes the fiber surface smooth and the active functional group be less,which leads to the poor interfacial compatibility between the fiber and the matrix material,and it is difficult to play the role of high performance enhancements.Therefore,surface modification of aramid fiber is the key to obtain high performance composite materials.At the same time,the functional application of aramid fiber has become a hot spot of research.The functional aramid fiber has potential application value in the fields of conductive,electronic shielding and antibacterial materials.The surface modification,functionalization and application of aramid fiber are explored in this paper.The surface modification of aramid fiber was studied,and the surface modification method of aramid fiber was explored.The aramid fiber of functional silver plating was carried out,and the method of functionalization of aramid fiber was explored.The poly（lactide）was reinforced by aramid fiber,and the application of aramid fiber reinforced resin matrix composite was explored.（1）The surface modification of aramid fiber was studied.The calcium chloride ethanol solution and dopamine solution were used to modify the aramid fiber.The chemical composition and structure,microstructure,roughness,tensile strength of the monofilament of the aramid fiber and the change of interfacial properties of aramid fiber/epoxy resin composite were studied.And the UV resistance of modified aramid fibers were studied.The results show that when the fiber is treated with CaCl₂ ethanol solution and dopamine solution successively,the surface of the aramid fiber can form a dense and uniform polydopamine coating,the surface roughness increases,the surface active group increases,the ILSS of the composite increases,the damage of the surface structure of the fiber is smaller and the falling range of the tensile strength of the monofilament is smaller.This method is better than the single method in improving the comprehensive effect.The UV aging test showed that the UV resistance of the aramid fiber was improved after CaCl₂ ethanol/dopamine treatment,which was due to the UV shielding effect of the polydopamine deposition on the fiber surface,which weakened the UV aging damage of the fiber.（2）On the basis of the surface modification of aramid fiber,the modified aramid fiber was functionalized by electroless silver plating,and the surface chemical composition,microstructure,thermal stability and electrical properties of the aramid fiber were studied after the functionalization of aramid fiber.The results show that the modified aramid fiber is treated by electroless silver plating,the poly（dopamine）can adsorb more silver ions.At the same time,it has the ability to reduce the silver ion in situ,and it can be used as a reductant in the silver plating reaction.By adding reducing agent,it can promote the formation of continuous,uniform and dense nano silver layer on the surface of the fiber.When the concentration of AgNO₃ reaches20g/L,the silver layer on the surface of the fiber is stable,and the resistance value tends to be stable.（3）On the basis of the surface modification of aramid fiber,the aramid fiber was added to the poly（lactic acid）,and the aramid fiber/poly（lactic acid）composite samples were prepared by the melting method.The changes of thermal properties,crystallization,cross section morphology,mechanical properties,rheological properties and MFR value of aramid fiber/poly（lactic acid）composite samples were investigated.The effects of fiber concent on the properties of the composite samples were also compared.The results show that the crystallinity of poly（lactic acid）increases with the addition of aramid fiber,and the aramid fiber can promote the formation of poly（lactic acid）αcrystal,and the compatibility of modified aramid fiber with poly（lactic acid）is better,and their interfacial bonding performance is better.At the same time,when the modified aramid fiber is added to 1.5%,the fiber is agglomerated.It makes it difficult to combine fiber with poly（lactic acid）.After the aramid fiber is added,the tensile strength of the poly（lactic acid）is improved.The steady viscosity and the complex number viscosity of the aramid fiber/poly（lactic acid）composite simples are increased,and the MFR value of the composite samples are also smaller than that of the pure PLA.