Interaction balances and properties of filled polymers

Abstract The dispersion behavior of calcium carbonate (CaCO₃), of mica and of sized sand fractions in poly(vinyl chloride) (PVC) and polypropylene (PP) has been evaluated using fillers with various surface treatments. Mechanical properties of the compounds were also studied in order to question the role of interfacial forces in the context of dispersion and property parameters. Surface characteristics of polymers and fillers were obtained from inverse gas chromatography data. It has been shown that in the acidic PVC matrix, rapid dispersion of fillers is favored when strong acid‐base interactions exist at polymer filler contacts. Similarly, mechanical properties at large extension are improved by acid‐base interactions. In contrast, for polypropylene (PP), a van der Waals force material, fillers without pronounced acid or base surface characteristics tend to disperse more rapidly and produce mechanically stronger compounds. The importance of filler surface properties and thus, apparently, of acid‐base interfacial forces varies directly with increasing particle size of the dispersed phase.