As shown in Figs. 4 and 5, the control NRLFs and the RHP-incorporated NRLFs had weight loss corresponding to the volatilization of the degraded samples. The control NRLF and RHP-incorporated weight loss from 350 °C to 590 °C was related to the decomposition of the natural rubber and cellulose content in RHP. Lignin in RHP, which decomposed at a high temperature, also contributed to the weight loss of the RHP-incorporated NRLFs (Sharma and Rao 1999). Thermal stability of a polymer is enhanced by increasing the char residue, as the formation of char hinders the diffusion of the volatile decomposition products (Alexandre and Dubois 2000). Similarly, as shown in Table 2, the final char residue increased with increasing RHP filler loading, thus contributing to a higher thermal stability. The improvement of the thermal stability of the RHP-incorporated NRLFs can also be attributed to the good dispersion of RHP in the NRLF,