Abstract
Thermoreversible gels of blends of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) in ${\gamma}$-butyrolactone solution were prepared, and the effects of the addition of amorphous PMMA to the solutions on gelation mechanism, sol-gel transition and gel morphology were investigated. Gels of PVDF/PMMA blends could be obtained when the weight percent of PVDF in the blend is 40% or lower, and the sol-gel transition temperature decreased with the increase of PMMA. The size of spherical gels observed by scanning electron microscopy was dependent on the gelation temperature and weight percent of PMMA. Gels prepared at the gelation temperature of 4$0^{\circ}C$ were the largest in size regardless of weight percent of PMMA, and the gels obtained from 80/20 PVDF/PMMA blend solution showed the largest size among the gels formed at 4$0^{\circ}C$. These phenomena were considered to be due to the competition of crystallization and liquid-liquid phase separation of solution. At low temperatures, gelation occurred dominantly due to crystallization. However, it is due to phase separation of the solution at high temperatures even though crystallization followed the gelation. This is consistant with the turbidity measurement results.
