The dispersion of the wood flours in the rPP matrix (Fig. 5(b)) is uniform as compared to vPP matrix (Fig.
4(a)). This may be due to the different grade of plastic and other impurities in the rPP. In some cases, the
part of the wood lumen is filled with plastic that could increase the strength of the composites because of
mechanical interlocking. When wood content is increased, the polymer matrix is no longer continuously
distributed and many wood flours are in direct contact with one another, resulting in poor bonding at
adhesion at the interface.