Crystallization kinetics and morphology of nylon 1212

The isothermal and non-isothermal crystallization processes of nylon 1212 were investigated by polarized optical microscopy. The crystal growth rates of nylon 1212 measured in isothermal conditions at temperatures ranged from 182 to 132 °C are well comparable with those measured by non-isothermal procedures (cooling rates ranged from 0.5 to 11 °C/min). The kinetic data were examined with the Hoffman–Lauritzen nucleation theory on the basis of the obtained values of the thermodynamic parameters of nylon 1212. The classical regime I→II and regime II→ III transitions occur at the temperatures of 179 and 159 °C, respectively. The crystal growth parameters were calculated with (100) plane assumed to be the growth plane. The regime I →II→ III transition is accompanied by a morphological transition from elliptical-shaped structure to banded spherulite and then non-banded spherulite. The development of morphology during isothermal and non-isothermal processes shows a good agreement.