The turning point on plots of log ϕ and log t of Mo's equation

Abstract

AbstractBACKGROUND: Mo's equation based on the Avrami equation and Ozawa equation has been successfully used in non‐isothermal crystallization kinetics by many researchers. However, in recent years we have found that plots of log ϕ–log t of Mo's equation are not straight lines, but there appears a turning point at ϕ = 7 °C min−1 or so. The aim of this article is to analyze in detail the reason for the occurrence of this turning point by studying the non‐isothermal crystallization of poly(vinylidene fluoride) (PVDF) using differential scanning calorimetry.RESULTS: A turning point at about 7 °C min−1 appeared on plots of log ϕ–log t. The cooling rate where the turning point occurred showed little change with increasing relative crystallinity, but the temperature decreased. It is noted that this turning‐point temperature is lower than transition temperature of regime I → II reported for PVDF.CONCLUSION: We deemed that the occurrence of turning points on plots of log ϕ–log t of Mo's equation can be ascribed to the different crystallization regimes based on the Hoffman nucleation theory, and presumed that the turning point corresponded to transition of regime I → II. Finally, we considered that Mo's equation should be analyzed using two beelines, instead of one beeline. Copyright © 2009 Society of Chemical Industry