Effects of PBO Fiber and Clay on the Mechanical, Morphological, and Dynamic Mechanical Properties of NR/HDPE Blends

Poly(p-phenylene-2,6-benzobisoksazole) (PBO) and natural rubber (NR)/high density polyethylene (HDPE) composites were melt-blended in a Haake internal mixer. The tensile strength, tensile modulus, and impact strength increased with fiber loading and optimized at 20%. Incorporation of clay into the NR/HDPE/PBO composites resulted in an improvement of tensile strength for NR/HDPE/PBO composites compared to the systems without clay. However, addition of clay was only effective at low contents (5-7.5%). Additional improvement of tensile strength, tensile modulus, and impact strength of the hybrid composite was observed on addition of liquid natural rubber (LNR). Scanning electron micrographs of the samples had indicated that the presence of clay decreased the domain size of the dispersed phase. Results on dynamic response showed that incorporation of clay and LNR into the composites had increased the storage modulus and reduced the tan delta. The shift of glass transition temperature (T(g)) to higher values for composites also indicated good interaction between the fiber and the matrix. POLYM. ENG. SCI., 51:419-425, 2011. (C) 2010 Society of Plastics Engineers