Influence of polymer matrix and coupling agents on melt flow behavior of wood filled polyethylene composites

The influence of coupling agents on the melt rheological properties of HDPE/wood flour composites has been investigated in this work by means of a capillary rheometer. Scanning electron microscopy was also employed to supplement the rheological data. It was found that molecular weight and molecular weight distribution of the polymer matrix and coupling agent characteristics influence the melt flow properties of the filled composites. Generally, low molecular weight and narrow molecular weight distribution polyethylene matrix provides larger increase of the viscosity of the composites with respect to the unfilled resin. Coupling agents tend to increase the resistance to shearing, but wall slip effects may interfere with the measured values, especially at very high filler loadings.