Flexural properties and micromorphologies of wood flour/carbon nanofiber/maleated polypropylene/polypropylene composites

The effects of carbon nanofibers (CNF) on the performance of three- or more phase composites are complicated. CNFs formulated into wood flour (WF)/maleated polypropylene (MAPP)/polypropylene (PP) composites by high shear blending alone improved flexural properties. Addition of an extrusion step after high shear blending enhanced CNF dispersion and improved the composites’ flexural moduli, but in these systems CNF did not contribute to flexural property enhancement. The addition of 1.0 wt% CNF to WF/MAPP/PP by high shear blending followed by extrusion did not affect either the WF dispersion or WF/PP adhesion. The adhesion between WF and PP/MAPP matrix was good (SEM), but CNF adhesion to the PP/MAPP matrix was poor.