Thermal degradation of nylon polymers

This paper is concerned with the processes of thermal degradation of nylon 6 and nylon 6,6, which lead to crosslinking and the production of involatil e char. The techniques used in this study include thermogravimetric analysi s (TG), differential scanning calorimetry (DSC), hot-stage Fourier transfor m infrared spectroscopy (hot-stage FTIR) and solution viscosity. TG results showed that nylon 6 and nylon 6,6 produce involatile char during thermal degradation. The formation of char lead to a deviation from first order kinetics of thermal degradation, and the amount of char yielded decre ased with increasing temperature. Thermal degradation lead to a decrease in the amount of crystallinity attai nable on cooling from the melt, which was considered to be due to crosslink ing, and was accompanied by an increase in molecular weight and formation o f colour. Hot-stage FTIR results showed that thermal degradation lead to th e formation of an aromatic-conjugated structure, which may contain keteneim ine groups. (C) 2000 Society of Chemical Industry.