Effect of the Incorporation of Modified Silicas on the Final Properties of Wood Adhesives

摘要

The effect of the incorporation of three different surface modified silicas on the final properties of poly(vinyl acetate) (PVAc) latex based wood adhesives is assessed. It is shown that the compatibility and reactivity of the silica with the polymer determines its state of dispersion throughout the polymer matrix. While silicas revealing the best compatibility with the monomer are located inside or close to the polymer particles surface, the silica that presents the lowest compatibility with the monomer is located exclusively on the surface of the polymer particles. This is found to affect the properties of the adhesives as higher tensile strengths are measured in the presence of silicas with good compatibility with the monomer. The reactivity between one of the silica modifiers and the polymer is the key to substantially improve the hydrophobicity and the adhesion of hybrid PVAc based adhesives.