Structure formation of polyamide 6 from the glassy state by fast scanning chip calorimetry

Fast scanning chip calorimetry has been employed to explore the kinetics of structure formation of polyamide 6 from the glassy state. First, the condition to obtain fully amorphous polyamide 6 has been evaluated. It was found that ordering processes are only permitted on cooling the relaxed melt slower than about 150 K s−1; faster cooling was connected with complete vitrification of the supercooled liquid. Cold-ordering of fully amorphous, non-aged samples on continuous heating only takes place if the heating rate is lower than 500 K s−1. Isothermal cold-ordering experiments of fully amorphous samples have been performed in a wide temperature range between 330 and 470 K, in order to obtain for the first time a complete relationship between half-time of cold-ordering/crystallization and temperature. The study was completed by an initial discussion of the temperature dependence of the mechanism of nucleation and of the effect of the crystal/mesophase polymorphism on the transition kinetics.