The thermal decomposition of poly(α,α,α′,α′-tetrafluoro-p-xylylene) (parylene AF-4) films with thicknesses of ca. 7.5 and 10 μm has been studied by both dynamic (10°C min−1) and isothermal TG in either nitrogen or oxygen atmospheres.
In dynamic studies with nitrogen, gross decomposition occurs between 546.7±1.4 and 589.0±2.6°C, with 26.8±4.4% of the initial
mass remaining at 700°C. With oxygen as the purge gas, the onset of decomposition shifts slightly to 530.8±4.2°C. The end
of the transition at 587.4±2.6°C is within experimental error of the nitrogen value, but no polymer remains above 600°C.
Isothermal data were obtained at 10°C intervals from 420 to 490°C in nitrogen, and from 390 to 450°C in oxygen. Plots of log(Δ%wt/Δt)vs. T−1 are linear throughout the specified range for oxygen and from 420 to 470°C for nitrogen. The calculated activation energies
of (147±16) kJ mol−1 and (150±12) kJ mol−1 in N2 and O2, respectively, are equal within experimental error.