AbstractPoly(α,α,α′,α′‐tetrafluoro‐p‐xylylene) was prepared by the pyrolysis of cyclo‐di‐(α,α,α′,α′‐tetrafluoro‐p‐xylylene) and by the pyrolysis of α,α′‐bis(alkylsulfonyl)‐α,α,α′,α′‐tetrafluoro‐p‐xylene. The pyrolysis of α,α′‐dibromo‐α,α,α′,α′‐tetrafluoro‐p‐xylylene also gave the polymer, but the method is less satisfactory. Poly(α,α,α′,α′‐tetrafluoro‐p‐xylylene) shows remarkable thermal and oxidative stability at elevated temperatures. Useful mechanical and electrical properties are retained after aging for 3000 hr at 250° in air. After initial change due to crystallization, tensile strength remains near 10,000 psi, elongation above 5, an
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