Thermal behaviour of poly[imino(1‐oxooctamethylene)], nylon 8

Abstract The thermal behaviour of nylon 8 was studied by differential scanning calorimetry (DSC). Glass transition temperatures (Tg) were measured over the molecular weight range 1,7·103 – 3,4·104 in order to determine a Tg‐Mn dependence. A small decrease in the Tg values was observed for the lowest molecular weight samples which, however, were obtained by polymerization in presence of a chain terminator. The origin of multiple melting endotherms, found during DSC analysis of samples crystallized under different conditions, was also investigated. The effects of heating rate, of cooling rate from the melt, and of isothermal crystallization at various crystallization temperatures (Tc) on melting behaviour were consistent with the hypothesis of a meltrecrystallization process during heating.