Phase and state transition effects on dielectric, mechanical, and thermal properties of polyols

The present study investigated the glass transition, crystallisation and me lting behaviour of erythritol, xylitol, and glucitol (sorbitol) using diele ctric analysis (DEA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). Sorbitol and xylitol were plasticised by water a nd their glass transition temperatures decreased when water content was inc reased, Erythritol crystallised rapidly, and its water plasticisation behav iour could not be determined. Melting of the crystalline polyols occurred a t their specific melting temperatures. Melts of erythritol and xylitol crys tallised on recooling and no glass transition was apparent on reheating. Qu ench cooled sorbitol melt remained amorphous and showed a glass transition on reheating. Glass transition and crystallisation were apparent in the DSC thermogram. and the dielectric and the dynamic mechanical spectra of mixtu res of amorphous and crystalline xylitol. (C) 2001 Elsevier Science B.V. Al l rights reserved.