Fabrication optimization of polypropylene composites reinforced with steam-exploded wood flour by wet process

Abstract

To take advantage of the unique characteristics of the wood flour by combining them with plastic in conventional panel pressing methods, a wet process was developed to make composites using polypropylene and steam-exploded (SE) flour from small-diameter loblolly pine. Wet-laid wood flour/polymer composites were fabricated using a standard TAPPI handsheet method followed by compression molding. The variables that may affect the product properties were investigated using an orthogonal test design. The results revealed that the modulus of elasticity (MOE) of composites increased, while modulus of rupture (MOR) decreased with increasing SE wood flour content. Both MOE and MOR of the composites increased with maleic anhydride grafted polypropylene content. Dynamic mechanical analyzer and differential scanning calorimetry measurement gave insight into the structure of these composites, and scanning electron microscope was used to characterize the interfacial adhesion.