NMR Studies of Molecular Motion and Compatibility in Polymer Blends of Poly(epichlorohydrin)/Poly(methyl methacrylate)

Abstract

Molecular motion of polymer chains depends on blending and differs in bulk and in polymer blend. In this research the molecular motion of poly(epichlorohydrin) (PECH) was studied by 13C NMR and showed different behavior in bulk from polymer blend. Two types of blend films, PECH/poly(methyl methacrylate) (PMMA)=(60/40) (wt%), were prepared from toluene and tetrahydrofuran (THF) solution; the former is transparent and the latter is opaque film. The line shape and temperature dependence of T1 and T2 in PECH indicate that the molecular motion of PECH is inhibited by surrounding PMMA chains and that the decrease in molecular motion depends on miscibility. The slow motion described by T2 is more influenced by blending than the fast one described by T1. Distribution curves of T2 were obtained for bulk and three types of blend films prepared from toluene, THF, and THF/H2O solution. The bulk and blend 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 the gradient in local concentration. T1 in PMMA agrees with T1 and T2 in PECH.