Comparing Crystallization Kinetics between Polyamide 6 and Polyketone via Chip‐Calorimeter Measurement

Polyamide 6 and aliphatic polyketone exhibit similar melting points and heats of fusion, which expose the kinetic effects of intermolecular interactions on their crystallization kinetics. The commercial chip‐calorimeter Flash DSC1 is employed to measure their crystallization rates in a broad temperature range. The results show that polyamide crystallizes faster than polyketone at high temperatures, but slower at low temperatures. The faster crystallization is attributed to a lower lateral‐surface free energy for crystal nucleation at high temperatures on account of the sheet‐like hydrogen bonding in polyamide crystals. The slower crystallization is attributed to the lower molecular mobility for crystal nucleation at low temperatures on account of the higher glass transition temperature of polyamide. Polyamide 6 (PA) and polyketone (PK) share similar thermodynamic factors in crystallization kinetics, such as melting points and fusion heats; therefore, their different crystallization rates expose the kinetic factors: A higher molecular mobility for PK crystallizing faster at low temperatures, and a lower surface free energy of crystal nuclei for PA crystallizing faster at high temperatures.