Multiple melting endotherms in melt-crystallized nylon 10,12

The melting behaviour of melt-crystallized nylon 10,12 was investigated by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (W AXD). The results show that all nylon 10,12 crystals obtained under various conditions, including isothermal, non-isothermal and stepwise crystallizat ion, and also after partial melting or annealing, show multiple melting beh aviour. It was found that each melting endotherm has a different origin. Th e highest melting peak corresponds to melting of the recrystallized materia l while the other melting endotherms are related to melting of lamellae wit h different thicknesses developing under different crystallization conditio ns. The equilibrium melting point of nylon 10,12 was also firstly estimated to be about 206 degreesC. (C) 2001 Society of Chemical Industry