Preparation and properties of melt-spinning fluorinated ethylene propylene fibres

Abstract

In this work, a novel fibre, fluorinated ethylene propylene (FEP) filament, was fabricated by melt-spinning. In addition, the properties of FEP fibres were investigated through apparent morphological observation, tensile testing, dry-hot shrinkage, differential scanning calorimetry, thermogramitric analysis (TGA) and Fourier transform infrared spectroscopy. Apparent morphological observation shows that FEP fibres present circular cross-sections and smooth surfaces. Just like the conventional fibres prepared by melt-spinning, such as poly (ethylene terephthalate) (PET) and polyamide 6, the stress–strain curves of FEP fibres show obvious stress yield points. The elastic recovery ratio of FEP fibres (80%) is much greater than that of polytetrafluoroethylene (PTFE) fibres (40%), endowing FEP textiles good wrinkle resistance. When FEP fibres are deposited in flame, smoke and droplets do not appear but shrinkage does occur. After treatment in hot air, the breaking strength of FEP fibres decreases, but the elongation at break increases. The melting temperature of FEP fibres is as closely high as that of the PET fibres, while the crystallization temperature is much higher, which puts forward greater challenges for FEP spinning. Compared with PTFE fibres, the crystallinity and the melting temperature of FEP fibres are much lower. TGA results demonstrate that FEP fibres present excellent thermal stability that is as stable as that of the PTFE fibres.