Abstract
Melting behavior of hydrogels of syndiotacticity-rich PVA derived from poly(vinyl pivalate) was investigated. One point six gram per deciliter aqueous solution of PVA with diad-syndotacticity of 61.2% (s-PVA(L)) turned to a gel when left standing at 2°C. Hydrogel made from 6 g⁄dl s-PVA(L) solution showed the melting temperature of 90°C. Melting temperatures of hydrogels of PVA with diad-syndotacticity of 68.7% (hs-PVA(L)) were above 100°C. The apparent enthalpy of fusion of a junction point in s-PVA(L) hydrogel was estimated to be 102 kJ⁄mol and this value was 2.6 times that of atactic PVA derived from poly(vinyl acetate).
