Self-decelerated crystallization in blends of polyhydroxyether of bisphenol A and poly(ethylene oxide) upon isothermal crystallization

The growth of spherulites of poly(ethylene oxide) in blends with poly(hydro xyether of bisphenol A) was investigated. In a very narrow range of crystal lization temperatures, the spherulite growth deviates from the usual consta nt growth rate regime in a systematic manner in which the growth rate decre ases with time. This is explained by local and overall changes in the compo sition with the proceeding crystallization that are due to the competition between the crystallization and diffusional chain displacement rates? respe ctively. These kinetic phenomena and processes can quantitatively be descri bed by a suitable analysis of the experimental findings. Deceleration is pr edominantly caused by a slowing of the chain motion by the glass-transition temperature being approached (i.e., vitrification) and, to a lesser extent , by dilution. (C) 2000 John Wiley & Sons, Inc.