GLASS-TRANSITION IN POLY(VINYLPYRROLIDONE) - EFFECT OF MOLECULAR-WEIGHT AND DILUENTS

Amorphous poly(vinylpyrrolidone) (PVP) varying in molecular weight (MW) (10 000, 24 000, and 40 000) was used to study the effect of molecular weight on the glass transition temperature (T(g)). T(g) was measured by differential scanning calorimetry (DSC). Blends with several diluents (water, butylamine, glycine, hexanal, xylose, glucose, and lysine) were also analyzed and the effect of blend composition on T(g) was evaluated. The effect of average molecular weight and of composition in the blends of PVP-plasticizer on T(g) was well described by previously reported relationships developed for synthetic polymers. The quantitative results obtained can be used for formulation of mixtures with known T(g) and for prediction of their behavior in storage.