Tensile strengths of the composites slightly decreased while the tensile modulus improved as the filler loading and crosshead speed increased, but the composites had an acceptable strength up to a filler loading of 40 wt.%. RHF could be utilized as a biodegradable filler at end-of-use in polymeric materials to minimize environmental pollution rather than produce strong reinforcing filler. As the filler loading and crosshead speed increased, the tensile property became more brittle, and the poor interfacial bonding between filler and matrix polymer caused decreased tensile and Izod impact strength of the composites. Nevertheless, this problem could be reduced by using a compatibilizing or coupling agent, and further extended research is suggested. As the test temperature increased, the thermoplastic polymer was softened and the composite showed plastic matrix deformation, which decreased the tensile strength and modulus. Fig. 9 presents the typical stress–strain curves of the composites according to various crosshead speeds and test temperatures in the tensile tests. As the filler loading increased, morphological study revealed more filler particles and increased numbers of holes where filler particles have pulled out traces.