Rheology and morphology of poly(vinyl acetate) + calcite films

We have studied mechanical and rheological behavior of poly(vinyl acetate) (PVAC) composites filled with calcite as a function of filler particle geometry, particle size distribution, and active surface area. Detailed morphological characteristic were investigated. Tensile properties of PVAC composites were evaluated in the composition range 5–20 wt% calcite. The elongation at break decreases as consequence of matrix mobility restriction by filer particles. By contrast, the strength at break increases as a result of fewer stress concentration points produced by small calcite particles. Large calcite particles decrease the strength of the PVAC composite because of lack of structural continuity. Failure is then dominated by the dewetting. Understanding the deformation as it relates to structure, mechanism of failure, and strength of interactions makes development of improved PVAC composites for adhesives possible.