Supermolecular structure of wood/polypropylene composites: I. The influence of processing parameters and chemical treatment of the filler

Wide-angle X-ray scattering (WAXS) and scanning electron microscopy (SEM) were used to investigate the effect of chemical modifications of wood as well as processing parameters on the supermolecular structure and morphology of wood/polypropylene (PP) composites. The surface of the filler was modified to enhance the adhesion between hydrophilic cellulose and hydrophobic polymer. Wood modification was performed by esterification with anhydrides (maleic, propionic, phthalic, crotonic and succinic) and by physical treatment with NaOH. The composites for structural characterization were prepared by the compression moulding method and injection technique. A new design of the compression mould, which ensured the wood pulling, was proposed. It was found that the polymorphs of PP matrix developed due to melt-shearing strongly depended on the pulling temperature as well as on the type chemical modification of wood. The modification of wood caused a significant decrease in the ability to generate the hexagonal phase of PP. Moreover, at a higher temperature of the mould, the amount of hexagonal phase of PP matrix slightly decreases. These investigations are very significant because characterize influence of real parameters processing as well as surface modification of filler on structure of composite materials.