Decomposition of poly(perfluorinated ethers): Effect of end groups on main-chain degradation and product formation

The decomposition of polyperfluorinated ether copolymers containing perfluoroethylene oxide, -CF2CF2O-, and perfluoromethylene oxide units, -CF2O-, capped by different end groups, -OCF3, -CH2OH, and -O(O=C)CH3, are investigated. Thus, the polymers are scissioned via an electron beam, and the subsequent chemistry is investigated. In all cases, the polymers lose mass, R-CFO on the ends of scissioned chains are produced, and volatile gases such as COF2 are evolved. The G values for polymer decomposition are 0.2-0.8; for gas evolution are 6-7; and for R-CFO end groups are ≃1.5. The end group -CH2OH has a significant effect on the chemistry after irradiation. The oligomeric R-CFO groups produced upon irradiation react with the -CH2OH end groups to produce ester and HF via alcoholysis. The aldehyde -CHO is also produced as a result of direct electron beam irradiation.