GEL FORMATION BY LOW-TEMPERATURE CRYSTALLIZATION OF CONCENTRATED PVA AQUEOUS SOLUTION

摘要

PURPOSE:To easily obtain a high-strength gel of high water content without repeated lyophilization or freezing/fusing, by separating a concentrated PVA aqueous solution, at temperatures below the icing point, into ice-phase and polymer-phase to make a phase-separated structure followed by crystallization of said polymer-phase at temperatures above the icing-point. CONSTITUTION:A concentrated PVA aqueous solution (10-30W/W%) is separated, at temperatures below the icing point (at =-5 deg.C pref. at -20 deg.C), into ice- phase and polymer-phase to form a phase-separated structure followed by crystallization of said polymer-phase at temperatures above the icing point (at 0- 10 deg.C for =10hr). Said PVA is =95 (pref. =99) mol% and =1,000 (pref. =1,700) in the saponification degree and average polymerization degree, respectively.