Kinetic analysis of thermal and thermo-oxidative degradation of polyethylene (nano) composites

Thermal properties and degradation of polyethylene LDPE (nano)composites were investigated by isoconversional thermogravimetric analysis in air and nitrogen atmosphere by applying the Kissinger-Akahira-Sunose method. Low-density polyethylene (LDPE) composites containing 3 wt.% nanofiller Cloisite 20A and 4, 6, and 8 wt.% of natural zeolite were prepared using extrusion/injection moulding. The parameters of thermal stability of the samples were determined i.e. onset temperature of the degradation (T-90), which exhibit initial mass loss (10 mass %) and maximum loss rate temperature (T-max). Also, activation energy (E-a) of samples was calculated and interpreted in terms of thermal degradation mechanisms. Under nitrogen, the thermal degradation of LDPE (nano)composites follows a random scission pathway but it was retarded and slowed by the presence of the fillers. The results show that thermo-oxidative degradation of studied (nano)composites is induced at lower temperatures and appears as much more complex and multi-stage process.