Phase Behavior and Physical Gelation of High Molecular Weight Syndiotactic Poly(vinyl alcohol) Solution

摘要: The physical gelation behavior of high molecular weight (HMW) syndiotactic poly(vinyl alcohol) (S-PVA) was investigated in consideration stereoregularity the polymer. To precisely identify effect stereoregularity, diad (S-diad) contents PVAs with similar weights were controlled to 61.5, 58.2, and 55.7%, respectively. gel point (GP) HMW S-PVA solution determined by observing frequency-independent loss tangent crossover between relaxation exponents from oscillatory shear experiment. process S-diad content over 58.2% divided into two types respect concentration solution. first type is that took place directly sol a clear GP which well coincident macroscopic temperature (Tgel). This for higher regime. second one occurred gradually accompanying evolution gel-like propertie...