Interface Structure and Properties of Polypropylene/Wood Flour Composites Reinforced with Grafted Polypropylene Compatibilizer

Abstract

In this work, a new compatibilizer, ternary monomer grafted polypropylene (hereafter shorted as: G‐PP), was successfully synthesized by solid phase grafting of maleic anhydride, methyl methacrylate, and butyl‐acrylate onto polypropylene. For all developed polypropylene matrix composites, the prepared G‐PP evidently showed enhancing mechanical properties on PP/wood flour (WF) composites, which is obviously superior to those from maleic anhydride grafted polypropylene (W‐PP) and virgin polypropylene (C‐PP). In particular, the wettability of G‐PP was greatly improved, while the melting temperature and β crystal phase amounts of the WF composites with G‐PP are much higher when compared to that of W‐PP and C‐PP. This can be reasonably explained by the formation of continuous micropores and filaments in WF composites containing G‐PP, as verified by hot stage polarizing optical microscope (POM). Meanwhile, the G‐PP effectively reduced movement of molecular chains of WPC and formed a better interface layer with WF, which contributed to penetrate more deeply and form micro‐crosslinking in the WF layer. We believe that the results reported in this work will increase the added value of polypropylene based wood plastics composites (WPC) and allow WPC to participate in lightweight and environmentally friendly products.