CRYSTALLIZATION OF POLYMER MELTS UNDER FAST COOLING .1. NUCLEATED POLYAMIDE-6

Samples of nucleated polyamide 6 were quenched from the melt so as to monitor cooling histories. Their morphology and crystal structures were discussed in relation to sample thermal history; cooling history relevant to quenched sample morphology was recognized as being confined in the interval 110 to 160-degrees-C. In particular, samples were essentially amorphous for cooling rates larger than 200-degrees-C/s. The gamma-crystalline form was observed for cooling rates in the interval 70 to 200-degrees-C/s, whereas alpha-crystalline structure was found dominant for yet lower cooling rates. Crystallinities evaluated from densities of quenched samples were compared with predictions of an isokinetic form of the Avrami model for polymer crystallization kinetics.