Abstract: The objective of this study is to investigate the thermal degradation behavior, degradation temperature and maximum degradation rate of rubber seed shell (RSS), high density polyethylene (HDPE) and binary mixture of RSS and HDPE in a weight ratio of 20/80 (HDPE/RSS) at different heating rates of 10, 20, 30 and 50 K min-1 within temperature range of 323-1200 K under non-isothermal gasification conditions in argon atmosphere at flowrate of 100 mL min-1 and steam flowrate of 300 μL h-1 using thermogravimetric (TGA) approach.