Impact and flexural properties of stone‐ground wood pulp‐reinforced polypropylene composites

This study analyses the flexural and impact strength of polypropylene reinforced with stone ground wood pulp (SGWP) and the effect of a maleated‐polypropylene (MAPP) coupling agent on the mechanical properties of these composites. Composites prepared in the absence of the coupling agent showed a very light positive linear evolution of the flexural strength with the percentage of reinforcing fiber. In contrast, composites that included MAPP in their formulation presented highly noticeable improvements with fiber content. By applying mathematical modeling strategies, the flexural modulus has been analyzed using the Cox–Krenchel model. Similarly, the flexural and tensile strength factors for the reinforcing fiber have been defined and utterly allowed for the determination of intrinsic fiber flexural strength. POLYM. COMPOS., 34:842–848, 2013. © 2013 Society of Plastics Engineers