THE NATURE OF ANOMALOUS BEHAVIOR IN THE K INETICS OF CRYSTALLIZATION OF POLY(ETHYLENE OXIDE) POLY(PROPYLENE OXIDE) MIXTURE

Kinetics of isothermal crystallization in the mixture of poly(ethylene oxide) (PEO) with M = 4000 and poly(propylene oxide) (PPO) with M = 4 25 was studied. Above a certain temperature characteristic of each com position of the mixture studied, crystallization was shown to be proce ed in two stages. Analysis of such crystallization based on the kineti c theory of polymer crystallization demonstrated that the first stage of crystallization was associated with chain folding, similar to that in a pure PEO. At the second stage, an increase in the crystallization rate was related to the transition to crystallization with extended c hains. This transition associated with the inflection point in the cry stallization isotherms was rationalized by a decrease in supercooling on expelling PPO to the volume amorphous phase. The position of the in flection point was shown to be controlled by the concentration of the components in the amorphous phase at the onset transition and crystall ization temperature, and not by initial concentration of the component s in the amorphous phase. The dependence of the composition of the amo rphous phase at the onset of transition on crystallization temperature was qualitatively described by the theory of secondary nucleation.