ELECTRON-BEAM IRRADIATION OF POLYPERFLUOROETHERS - EXPERIMENTAL-ANALYSIS OF MAIN-CHAIN DEGRADATION

The electron beam irradiation of polyperfluorinated ethers are investi gated. Main-chain scissioning is the predominant effect, inducing a we ight loss in the bulk materials caused by evolution of small gas molec ules such as COF2 and CF4. The G values for main-chain scissioning, ma ss loss, and gas evolution are determined from experiment and correlat ed to structural differences. From these results we conclude that unbr anched polyperfluoroethers degrade more efficiently and produce more C OF2 than branched polymers when the monomer units contain -CF2-CF2-O- and/or -CF2O- in the main chain. With a pendant perfluoromethyl, -CF(C F3)-CF2-O-, or an additional carbon atom in the main-chain monomer uni t, -CF2-CF2-CF2-O-, the electron beam induced degradation is comparati vely less efficient; in the branched polymers, CF4 evolution competes with COF2 formation.