Effects of Residual Solvent on Glass Transition Temperature of Poly(methyl methacrylate)

Abstract

The effects of residual solvent on the glass transition temperature (T_g) of poly(methyl methacrylate) (PMMA) were studied. A small amount of solvent in a film obtained by solution casting was found to remain even after vacuum evaporation for 30 h and compression-molding at 200 °C. The amount of residual solvent was less than 0.5 %, as revealed by gas chromatography. Therefore, this phenomenon is different from the plasticizing effect. A shift of the T_g to a lower temperature was attributed to strong ion-dipole interactions between the solvent molecules and the carbonyl group in PMMA molecules. Such interactions suppressed the associated states of PMMA, which greatly affected chain mobility.