Modification Of Carbon Fiber/Polyphenylene Sulfide Composite Based On Reduced Graphene Oxide

Carbon fiber(CF)reinforced polyphenylene sulfide(PPS)is a high-performance thermoplastic resin matrix composite material,because the surface of CF is inert,and the melt viscosity of PPS is very large.This makes the adhesion between CF and PPS poor and the formed interface strength is low.In order to improve the interface performance of CF/PPS composites,two modification methods are adopted in this paper:(1)graphene oxide(GO)is blended with PPS matrix,and after in-situ thermal reduction,reduced graphene oxide(RGO)is introduced into the composite interface layer.(2)the mixed solution of GO and epoxy resin(EP)was used to sizing CF.RGO/CF/PPS composites were prepared by these two methods.The research compares the interface performance before and after modification of composite materials,and the interface modification effect is analyzed.Firstly,RGO/CF/PPS composites were prepared by blending GO with PPS and hot pressing.In the non-isothermal crystallization process,RGO can improve the crystallinity of PPS,and as the RGO content increases,the crystallinity gradually increases.During isothermal crystallization,0.05%RGO can improve the crystallinity of PPS,but the higher content of RGO will hinder the crystal growth of PPS.When the GO content is greater than 0.1%,the maximum thermal decomposition temperature of PPS shows an upward trend.The ILSS results of the composite show that with the increase of RGO content,ILSS increases first and then decreases,when the GO content is 0.1%,the ILSS of the composite material is the most significant improvement,an increase of 18.4%.After the GO content exceeds 0.1%,the ILSS of the composites decrease.The storage modulus of RGO/CF/PPS is higher than that of CF/PPS,and the mechanical loss has decreased.Through microscopic morphological observation,a large amount of plastically deformed matrix resin adhered to the CF surface after shear failure,when the GO content does not exceed 0.1%,the interfacial bonding of RGO/CF/PPS composites is significantly improved,but the increasing RGO will form aggregates on the CF surface and affects the interface wetting,making the interface strength decrease.After the wet heat treatment of the composite material,the ILSS retention rate of RGO/CF/PPS is relatively lower than that of CF/PPS.At the same time,the mechanical loss of RGO/CF/PPS composites increases,and the glass transition temperature(Tg)increases.After interlayer shear failure,the surface of CF becomes smooth and the adhesion of resin greatly reduced.Some RGO/PPS interface damages also occurred.The RGO/CF/PPS interface bonding strength decreased at this time.Secondly,after surface sizing treatment of CF,RGO-EP/CF/PPS composites was obtained by hot pressing,when the GO content is 0.1%,the ILSS of the composite material reaches 44.1MPa,an increase of 6.8%.After the content exceeds 0.1%,the ILSS of the composites gradually decreases.After modification,the storage modulus of RGO-EP/CF/PPS increases,which is higher than that of CF/PPS,and the mechanical loss modulus has decreased,generally lower than CF/PPS.Through the observation of the interface micro-topography,PPS can adhere tightly to the surface of CF under the reaction of EP cross-linking.When 0.1%GO is added,the plastic deformation of the matrix resin adhered to the groove of the CF increases,and the interfacial bonding strength of the composite material is improved.After wet heat treatment,the ILSS retention rate of RGO-EP/CF/PPS is lower than that of CF/PPS,but Tg has increased.Under the swelling effect of water on EP,after the wet heat treatment,the pores at the interface of the composite material increase,and the defects formed also increase.The RGO-EP layer loses the modification and enhancement of the interface,and the matrix resin adhered to the CF surface reduced,so the interfacial adhesion performance of the composite material decreases.