Preparation And Properties Of Polyperfluoroethylene Propylene Fibers And Fabrics

With the wide application of fiber materials and their products in aerospace,medical and health care,environmental protection filtration and other fields,the requirement of fiber performance is getting higher.Perfluoropolymers have attracted much attention due to their excellent chemical resistance(such as acid,alkali and organic solvent),aging resistance and flame retardancy.Polytetrafluoroethylene(PTFE)is one of the most important perfluoropolymers.Its special regular structure endows it with excellent properties,but its "insoluble and immiscible" properties also limit its processing and molding.Poly(fluorinated ethylene-propylene)(FEP)is one of the modified materials of PTFE which has similar excellent properties as well as good thermoplastic processability.Therefore,FEP fiber can be prepared by melt spinning method.Graphene(GE),as a two-dimensional planar material with high-performance in the 21 st century,has excellent properties such as high strength,conductivity,hydrophobicity and lipophilicity,making it an ideal filler for the preparation of functional polymer composites.In this paper,FEP was used as raw material to study the preparation process,structure and properties of FEP fiber and fabric.Also,GE was used as filler to modify FEP matrix,and then the structure and properties of modified fiber were studied in detial.FEP fiber(POY type)was produced by twin-screw extruder,and the influence of drawing and heat setting process on its structure and properties was investigated.The results showed that the crystallization,orientation and mechanical properties of the fiber could be effectively improved by the drafting and heat setting process.The crystallinity,orientation and fracture strength of the FEP fiber which was stretched by200% were increased by 4.29,81.9 and 9.7%,respectively.The FEP fiber orientation was increased by 1.2%.The continuous and uniform FEP filament(FDY type)was prepared by step drawing with single screw melt spinning machine,and then the fabric was made with filament as raw material by textile technology.The structure and properties of the filament and fabric were studied.The results showed that FEP filament had good mechanical properties with the breaking strength was 0.78 c N/dtex,and the elongation at break was 21%.At the same time,it had excellent high temperature resistance,heat shrinkage resistance,chemical resistance and hydrophobicity with the water contact angle of yarn was 115.8°.Besides,the fiber fabric had good wear resistance,high temperature resistance,dimensional stability and mechanical properties,its longitudinal and latitudinal breaking strength were 29.4 and 24.5 MPa,respectively.After treatment with chemical reagents and aging experiments,the mechanical properties of the fiber fabrics had a little change,showing excellent chemical resistance and aging resistance.GE modified FEP fiber(POY type)was prepared by twin-screw extruder.The effects of GE content,drawing and heat setting treatment on the structure and properties of the modified fiber were investigated.The results showed that GE disperspropertied well in FEP matrix,and was not oxidized or denatured in the melt spinning process.The addition of GE reduced the crystallization and orientation of the modified fiber,while the drafting and heat setting treatment could effectively improve the crystallization and orientation of the modified fiber.GE also improved mechanical properties and lipophilic properties of the modified fiber effectively.When GE content was 0.3 wt%,the breaking strength of the modified fiber reached the maximum value(18.45 MPa),the young's modulus increased by 19.5%,and the kerosene contact angle decreased by 37.4%.GE modified FEP fiber had not only improved the comprehensive performance,but also retained the excellent chemical resistance of FEP matrix.Among them,after the chemical treatment,the retention rate of the tensile strength of the modified fibers was more than 95%.