NMR-STUDIES OF MOLECULAR-MOTION AND COMPATIBILITY IN POLYMER BLENDS OF POLY(EPICHLOROHYDRIN) POLY(METHYL METHACRYLATE)

Molecular motion of polymer chains depends on blending and differs in bulk and in polymer blend. In this research the molecular motion of po ly(epichlorohydrin) (PECH) was studied by C-13 NMR and showed differen t behavior in bulk from polymer blend. Two types of blend films, PECH/ poly(methyl methacrylate) (PMMA)=(60/40) (wt%), were prepared from tol uene and tetrahydrofuran (THF) solution; the former is transparent and the latter is opaque film. The line shape and temperature dependence of T-1 and T-2 in PECH indicate that the molecular motion of PECH is i nhibited by surrounding PMMA chains and that the decrease in molecular motion depends on miscibility. The slow motion described by T-2 is mo re influenced by blending than the fast one described by T-1. Distribu tion curves of T-2 were obtained for bulk and three types of blend fil ms prepared from toluene, THF, and THF/H2O solution. The bulk and blen d films cast from toluene show sharp distributions are homogeneous in molecular motions. The blend films cast from THF and THF/H2O have wide distribution in molecular motion, which indicates the existence of th e gradient in local concentration. T-1 in PMMA agrees with T-1 and T-2 in PECH.