5. Theory
The surface energy of material is a crucial property in determining
the wetting on the surface, which in fact governs the interface
characteristics of the two adhering surfaces. The strength of the
interface between reinforcing agent and the matrix plays an important role in determining the efficiency of stress transferred
from matrix to the reinforcing agent. The strength of the interface
in turn governs the overall strength of the composite. Complete
wetting of the matrix to the fiber or particulate surface provides
an opportunity to have intimate contact and thus adhesion between
the two. Wetting is an interfacial phenomenon that is governed
by the surface energy or tension of the two interacting
phases, in this case matrix (PHBV) and fiber (wood fiber) or inorganic
particulate (talc).