Gelation beaviour of a-PVA solutions in wide range of standing temperature and different DMSO/H2O blending ratio

摘要

Atactic poly (vinyl alcohol) (a-PVA) gels were obtained using mixed solvents of various ratios of water and dimethyl suloxide (DMSO) in wide range standing temperature between 50℃ and -78℃. The melting points of obtained a-PVA gels were measured by test-tube inversion method as the common determination test of gelation. With the decrease of the standing temperature at above 0℃, the sol areas gradually decreased in the order from medium DMSO content (30-80vol%) to high or low DMSO content (below 30vol% or above 80vol%). The gelation temperature of a-PVA solution with DMSO 60vol% could be up to 40℃. As for the freezing area, even if when standing temperature at -78℃ there still were nonfreezing areas at DMSO content 60 and 70vol%. When the standing temperature was below 0℃, the melting points of gels formed at the DMSO content of 30- 80vol% were not so different and independent of a-PVA concentration.