Carbon Fiber Surface Modification With Rapid Deposition Of Polyphenols And Click-Polymerization To Improve The Interfacial Properties Of Composites

When preparing composites,it is difficult to form a firm interface between CF and matrix,because of the smooth and lacking active groups surface of CF.Therefore,it is usually necessary to modify the CF surface,to change surface morphology,increase roughness,and change the chemical composition.The conditions of polyphenols deposition and co-deposition reactions are mild,and the deposition product can adhere to any materials.They also can act as a bridge for subsequent reactions,and have received lots of attentions in the field of CF surface modification.However,traditional polyphenols deposition reactions always need 8-24 h.Therefore,rapid polyphenols deposition methods are needed for modification of CF.The researches of CF surface modification mainly focus on introduction of functional groups,inorganic particles or grafting macromolecules,but there are few reports on growing polymer particles on the surface of CF.Clickpolymerization has the advantage of fast reaction speed,simple and mild reaction conditions.It is mainly used to prepare polymer particles,but there are few reports in the field of CF modification.Some methods of using clickpolymerization to modify CF have been studied in our laboratory,and great results have been obtained.However,in previous studies the glass transition temperature of click-polymer growing on the surface of CF is low,which makes it difficult to maintain morphology and properties after high temperature processing,and it is hard to use under high temperature.Therefore,the research idea of this paper is put forward:adding oxidants to accelerate the deposition and co-deposition reactions of polyphenols on CF surface,and using epoxy-sulfhydryl click-polymerization to adjust morphology and the properties of CF surface.For CF/epoxy composites,clickpolymerization layers with different Tg are growing on the surface of CF to improve the interfacial strength of the composites.For CF/PP composites,ODA was grafting on CF on the basis of click-polymerization,and the interfacial properties were improved by roughness improvement,molecular entanglement and interlocking.The main research contents are as follows:1.Rapid deposition of polyphenols to modify the surface of CF:The effects of adding different oxidants to accelerate DA deposition on CF were investigated,and NaIO4 was used to accelerate the deposition processing of DA,DA/PEI,CAT/TEPA on CF.The optimal amount of NaIO4 was investigated.The changes of surface morphology,surface roughness,elements content and group types,surface hydrophilicity of different CF were investgated.2.CF modification with click-polymerization to improve the interfacial properties of CF/epoxy composites:Click particles were grown on the surface of CF by thiol-epoxy clickpolymerization.The surface morphology,roughness,surface chemical compositions of CF and the Tg of click-polymer were investigated by changing-SH monomers.The influence of CF pre-treatment methods was investigated.The Tg of click polymer and the surface properties of CF were further adjusted by changing some of epoxy monomers.Finally,the effects of click-modification on the interfacial properties of CF/epoxy composites were investigated by droplet debonding test.3.CF modification with click-polymerization to improve the properties of CF/PP composites:Long chain structure of octadecylamine was constructed on the CF surface,on the basis of click-polymerization.CF/PP composites were prepared by hot pressing method using CFF after modified.Tensile and flexural properties of CF/PP composites were tested.The interfacial properties of CF/PP composites were investigated by droplet debonding test.