engleski

Morphology and failure in nanocomposites. Part II: Surface investigation

Polymer composites filled with calcium carbonate (CaCO3) nano fillers (<100 nm), and kaolin filler of layered structure, both well suited to create nanocomposites, were analysed. The aim of this study was to investigate the influence of surface properties of the filler and matrix on the adhesion parameters at the interface in composites. The inverse gas chromatography, contact angle and capillary measurements were used for the surface characterization of filler and matrix. Although these methods are based on different assumptions, we found the same trends in the effects of filler surface treatment and/or matrix chemical structure on the changes in the dispersive and polar components of the surface energy. The energetics of the filler and matrix were varied in order to investigate the work of adhesion, interfacial energy and coefficient of spreading, and their influence on the composite properties. We found that the surface treatment of calcium carbonate filler lowered the filler surface energy and the work of adhesion in composite with poly (vinyl acetate) matrix. The mechanical, thermal and morphological properties of the composite with treated CaCO3, measured in the first part of this paper, indicated a weak and thin interphase. In the composite with kaolin filler the higher interaction with the polyacrylate copolymer matrix based on styrene in comparison to the one based on methyl methacrylate, were confirmed by the higher work of adhesion at the interphase, resulting in a stronger reinforcing of the composite.

nanocomposite; interface; adhesion phenomena; contact angle; inverse gas chromatography; surface energy

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