The glass transition temperature of polyacrylonitrile has been determined for polymer varying in molecular weight from 8 × 103 to 3 × 106. Results could be represented by Tg = (96.5 ± 1.0) − (2.8 ± 0.1) × 105/M̄n, giving for the glass temperature of a polymer of infinite chain length, 96.5 ± 1.0°C. Specimens showing coloration gave enhanced glass temperatures attributable to the stiffening effect of conjugated ring structures, and were excluded from consideration of the effect of molecular weight. Determination of Tg were made on films prepared from solutions of polymer in dimethylacetamide, butyrolactone, and dimethyl sulfoxide in addition to dimethylformamide. Dependence on weight percentage of polymer, w2, for the range 90 < w2 < 100 was given by Tg = (3.19 ± 0.03)w2 − (232 ± 4), no specific solvent effect being observed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.