Abstract
Polyethylene single-crystal mats deformed by hot pressing were annealed in air at temperatures between 100°C and 130°C for 1 hour. The changes of heat of fusion and melting point with increasing annealing temperature have been investigated by differential scanning calorimeter.
The annealing behavior of compressed mats has been found to differ from that of drawn mats. For compressed mats it was observed that the heat of fusion passes through a maximum at an annealing temperature of 120°C and melting point shows no detectable change on annealing up to 115°C whereas it increases drastically at higher temperature over 120°C.
Experimental results were interpreted in terms of two mechanisms, i.e., the contraction of unit cell dimension and the thickening of lamella, each dominating below and above an annealing temperature of 120°C respectively.
