Investigation On Interfacial Macrostructure Modulation And Compatibility Of Nitrile-Based Polymer/Fiber Composites

Carbon fiber-reinforced matrix resins composites could meet the demands of materials with lightweight and outstanding properties in many fields.However,the interfacial compatibility between carbon fiber and matrix resin was one of the important factors that affected the properties of the composites.Thus improving the interfacial compatibility between carbon fiber and matrix resin by modification on carbon fiber surface had become one of the key research directions in the composites fields.Among of them,fabrication of microstructures on carbon fiber surface could improve the interfacial interaction through the physical meshing between microstructures and matrix resin.This method was widely adopted due to the general applicability and flexible modification methods.Currently,interfacial compatibility between carbon fiber and matrix resin was mainly investigated by the two aspects of macro-properties and microstructure transformation through the combination of mechanics and interfacial micro-morphology.However,macro-properties were complexly affected by many factors and microstructure transformation was difficult to reveal its physical effects.This fact resulted in that the mechanism of the improvement of interfacial compatibility through formation of physical meshing needed to be further investigated.Thus,in view of the poor interfacial compatibility of carbon fiber-reinforced composites,iron phthalocyanine（FePc）was utilized to fabricate different microstructures on carbon fiber surface and modified carbon fiber-reinforced Poly（arylene ether nitrile）（CF/PEN）composites were prepared.Rheological and dynamic mechanical analysis was applied to study the viscoelastic behavior of the composites.And the interfacial compatibility influenced by physical meshing and their mechanism were investigated by the perspective of molecular chain motion.FePc was prepared by three kinds of bisphthalonitriles with Fe Cl₃·6H₂O in NMP solvent by one-step method,respectively.Firstly,FePc was loaded on carbon fiber by sizing coating method and then soaked in solvent for a certain time,after that FePc modified carbon fiber was prepared through heat treatment.The effects of different factors on FePc microstructures formation and their formation mechanism were studied.Formation of FePc microstructures affected by introducing of phthalocyanine template onto carbon fiber surface,introducing of hydroxyl and imino groups into phthalocyanine template as well as introducing of carbon nanotube filler into FePc were further investigated,respectively.Then,resin solution was utilized to pre-impregnate carbon fiber fabric to prepare carbon fiber prepregs.Prepregs and PEN films were alternately laminated to fabricate carbon fiber/Poly（arylene ether nitrile）composites by hot pressing.Structure and thermal properties of FePc were characterized by FTIR,UV-vis,XPS as well as DSC and TGA.Results showed that FePc,prepared through bisphthalonitrile and Fe Cl₃·6H₂O,possessed excellent thermal properties.According to the characterizations of FePc microstructures morphology on carbon surface,XPS of FePc microstructures,UV-vis of FePc in soaked solvents and the morphology of FePc affected by heat treatment confirmed that granular,spiny and flake FePc microstructures formed from the three kinds of FePc on carbon fiber was through J-type aggregation.In addition,formation of FePc microstructure morphology was also affected by the conjugated structure and polar groups on fiber surface as well as the addition of carbon nanotubes.SEM and AFM were adopted to characterize the morphology,roughness and microstructure density of FePc microstructures on carbon fiber.By characterizing the water contact angle on fiber surface,it was found that the wettability of fiber surface would be decreased by the formation of dense and uniform FePc microstructure.Rheology and DMA were used to characterize the viscoelastic behavior of the composites.Relaxation process of the composites influenced by FePc microstructures was studied by linear viscoelasticity,storage modulus,viscosity,rheological Cole-Cole curves,creep resistance,T_g and glass transition activation energy of the composites.Then interfacial compatibility influenced by physical meshing was investigated from the perspective of molecular chain motion.Furthermore,the effects of microstructures on interfacial compatibility were also studied by the combination of fracture morphology and mechanical properties of the composites.Additionally,T_gs of the composites and PEN/FePc composite films were compared and analyzed by DSC,and the plasticizing behavior of FePc aggregates to PEN on carbon fiber surface was studied.Thermal conductivity,conductivity and electromagnetic interference shielding property of the composites with introducing of carbon nanotubes were preliminarily analyzed.In this dissertation,different FePc microstructures formed on carbon surface was regulated and controlled by various methods.The relationship between surface wettability and formation of physical meshing,influenced by different microstructures,was systematically studied.The effects of microstructures’geometry,roughness and density as well as different resin solution concentration,different resin infiltration mode on fiber surface and introducing of carbon nanotubes on physical meshing formation were systematically analyzed and investigated.Carbon fiber-reinforced PEN composites with outstanding structural and functional properties were prepared.Research methods applied to study the interfacial compatibility of continuous fiber reinforced composites were enriched.Based on the researches,it was provided a new technology and research techniques to improve and investigate the interfacial interaction of carbon fiber-reinforced thermoplastics composites.