ACTIVATION-ENERGY FOR CRYSTALLIZATION OF LOW-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE) AND LOW-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE) POLY(METHYL METHACRYLATE) BLENDS DETERMINED BY DSC AND POLARIZED OPTICAL MICROSCOPY/

The crystallization process of poly(ethylene oxide) (PEG) and PEO/poly (methyl methacrylate) (PMMA) blends in the low molecular weight region of PEO was studied by differential scanning calorimetry (DSC) and pol arized optical microscopy (POM). The half-time of the crystallization t(1/2), the time at which crystallinity X(t) = 1/2, was inversely prop ortional to the linear growth rate G of spherulite, i.e. t(1/2)(-1) pr oportional to G. The value of E characterizes the temperature dependen ce of the activation energy for the formation of a secondary nucleus o n the growing side surface of the crystal lamella and was evaluated fr om the t(1/2) measured by DSC. The value of E of PEO was not affected by blending PMMA. However, the slightly increasing tendency of E was o bserved for PEO and PEO/PMMA blends with increasing molecular weight o f PEO, M(PEO) This tendency may correspond to the crossover of E from low molecular weight material to polymer.