Study On Preparation And Properties Of Waterborne Polyurethane Sizing Agent For Carbon Fiber

Carbon fiber reinforced thermoplastic composites(CFRTP)have been the research focus in recent years due to their advantages of low cost,recyclability,easy processing and good toughness.However,most of the carbon fiber sizing agents used in industrial production are epoxy sizing agents,which do not match with thermoplastic resin,and even the use of epoxy sizing agents in the actual production process reduces the mechanical properties of thermoplastic composites.In order to solve the problem of lack of carbon fiber sizing agent suitable for thermoplastic resin,based on the principle of similar phase dissolution,two kinds of polyurethane with different structures were designed and prepared to water-based sizing agent,which was used to strengthen carbon fiber/polyamide 6 composites.(1)Due to the advantages of low viscosity and high functional group density of hyperbranched polymers,this paper designed and synthesized a hyperbranched polyurethane with UV resistance,and prepared water-based sizing agents of different concentrations by neutralization.According to the surface scanning electron microscopy photos of carbon fiber after sizing,the mechanical properties of carbon fiber /PA6 composites after sizing and the fracture surface morphology of composites,the optimal sizing agent concentration of 0.5% was selected.The interface strengthening mechanism of polyurethane sizing agent was studied and analyzed,and the ultraviolet resistance of sizing agent and composites was characterized.(2)with isocyanate itself and its synthesis process using phosgene are toxic,based on the environmental consideration,in this paper,using the biological source of epoxy soybean oil and carbon dioxide as raw material,main greenhouse effect multivariate ring carbonic acid,was synthesized through ring of carbonic acid and diamine ring opening reaction of isocyanate polyurethane(pu)was prepared.Non-isocyanate polyurethane was prepared by neutralization reaction with different concentration of water-based sizing agent.The optimum concentration of sizing agent was 1.0%.Since the ring-opening reaction between cyclic carbonate and diamines generates both carbamate bonds and hydroxyl groups,more hydrogen bonds can be formed at the interface,which has a better interfacial enhancement effect than the first experiment.