Preparation And Propertiees Of PPEK Emulsion Sizing Agent

With the development of aerospace industry, as well as people on the urgentdemand of high heat-resistant materials, carbon fiber reinforced thermoplastic resinbased composite materials are increasingly being recognized by people and widelyapplied. Especially CF/PPEK composite material, it is a kind of new typethermoplastic resin base composite material combined with the high heat resistanceand high mechanical properties. Generally, through the process of manufacturecarbon fibers are sized or coated with a very thin (usually on nanometer scale)coating of a prepolymer or resin for the purpose of inserting a polymer interlayerbetween the carbon fiber and the polymer matrix to improve the interfacialproperties and prevent the fibers from damage. At present, the sizing agents forcarbon fiber are epoxy resin system dominated. However, on the preparation ofCF/PPEK composite material, the wettability of resin and carbon fiber is poor, andbonding strength is also low, thus it has important significance to develop a newsizing agent, which could improve the interfacial properties of CF/PPEKcomposites.In this paper, PPEK emulsion type sizing agent was prepared, studied theinfluencing factors of emulsion stability in the process of preparation and its film-processing ability was also analyzed. Then coat the sizing agent on the desizingT700carbon fibers.The chemical species and functional group composition of unsized and sizedfiber were characterized by XPS tests, the results showed that PPEK sizing couldintroduce active groups into the surface of the carbon fiber, so that the carbon fibersurface polarity and infiltration capacity between carbon fiber and resin could beimproved; the surface morphologies of sizing carbon fibers were observed byscanning electron microscopy (SEM), SEM analysis showed that the mass fractionof0.5%is the best sizing concentration; By using atomic force microscope (AFM)observation on the surface fluctuation situation of the carbon fiber and the surfaceroughness, it found that PPEK sizing could increase the surface area of the carbonfiber, and improve the surface roughness; the thermal properties and fibermonofilament tensile strength were tested separately, compared with epoxy resinsizing agent, PPEK sizing agent had a better heat resistant performance, and itcould also improve the mechanical properties of fibers; meanwhile, the PPEKsizing fiber enhance more than unsized fiber in surface energy. Then，the interfacial properties of CF/PPEK were studied, the results showedthat wettability and interfacial shear strength are greatly improved, which meant thesizing agent could have an obvious enhanceing effects on the interfacial propertiesof CF/PPEK composites.