Effects of fibers on the glass transition temperature of polyphenylene sulfide composites

摘要

AbstractThe glass transition temperature (Tg) of polyphenylene sulfide (PPS), and of several commercial and model PPS prepregs with aramid, carbon, and glass fibers was studied by means of differential scanning calorimetry. TheTgof unreinforced PPS was found to range between 83–90°C, depending on source and molecular weight. TheTgof the commercial prepregs was depressed by about 3–5°C from that of the corresponding unfilled PPS, an effect that was ascribed to the plasticization of the PPS by one or more components of the fiber finish (size) that was assumed to have diffused into the PPS polymer. In the case of model prepregs prepared with finish‐free reinforcing fibers, an expected increase inTgwas observed. In model prepregs prepared with finished (sized) aramid fibers, theTgwas depressed as in the case of the commercial prepregs. With sized AS‐4 carbon fibers, theTgwas increased, but significantly less so than with unsized AS‐4 fibers. With sized glass fibers, the same slight increase inTgwas observed as with unsized glass fibers. The increase or decrease ofTgin all cases was a function of the fiber content in the model P