Radiolysis of fluoro ethylene-propylene copolymer

Full text: Poly(tetrafluoroethylene-co-perfluoropropylene) (FEP), is used for medical and sophisticated aerospace applications. where a specialty polymer with high radiation-stability is required. Hence, an understanding of the radiation chemical processes is important and will lead to the design and development of the appropriate material for different applications. FEP like other fluoropolymers exhibits unique characteristics such as resistance to chemical attack by solvents, chemical inertness, thermal stability, excellent weathering resistance and outstanding electrical properties. Combination of theses properties together with a radiation stable polymer provides an excellent profile for a polymer appropriate for applications mentioned previously. The behavior of FEP upon irradiation depends on the environment and the temperature of the radiolysis. The mechanical and physical changes for un-irradiated as well as irradiated FEP have been studied using NMR, DMA, TGA and the mechanism of the crosslinking and degradation was studied using ESR. FEP has been known to degrade when irradiated at room temperature. However, there is evidence that irradiation of FEP in vacuum at temperatures above its glass transition temperature will result in crosslinking reactions predominating over chain scission or degradation. The FEP under study is a linear, semi-crystalline fluoroplastic with the glass transition temperature of 84-86 deg C. This fluoropolymer is commercially produced by copolymerisation of tetrafluoroethylene and perfluoropropylene