COMPATIBILITY OF POLY(ETHYLENE OXIDE)-POLY(VINYL ACETATE) BLENDS

In the reported experiments, the compatibility of poly(ethylene oxide) EN DASH poly(vinly acetate) (PEO-PVA) blends was examined at five compositions covering the complete range. Samples were prepared by coprecipitation and solution casting. Dynamic mechanical properties were studied at 110 Hz between minus 120 and 65 degree C for dry, quenched, and annealed samples. The study also included tensile testing at 25 degree C, examination of blend morphology, and DSC measurements at elevated temperatures. Optical microscopy revealed that crystallization of PEO proceeds essentially unhindered at up to 25% poly(vinyl acetate) content by weight. Higher levels of this component drastically reduce spherulite size, and at the highest PVA compositions there was no evidence of crystallization. Thermomechanical spectra of quenched and annealed samples indicate limited mixing of the two componenets except for the higher ( greater than 75%) PVA compositions. Tensile properties show a mutual reinforcement at 10 EN DASH 25% PVA content due to possible polymer segment association. The melting-point depression of PEO is significant above 25% PVA and has been attributed to morphological changes of the PEO crystalline phase.