engleski

Surface and interface effects of nanoparticles in polymer materials

The optimal adhesion parameters i.e. the increased work of adhesion, lowered interfacial free energy and positive coefficient of wetting, was revealed as parameters for the effective adhesion at the interface between the selected nanoparticles and polymer matrix in comparison to its microcomposite counterparts. In this paper we will make an overview of our results about the surface effects of the selected calcium carbonate (CaCO3) nanofillers vs. microfillers in polyvinyl acetate (PVAc) and/or polyurethane (PUR) matrix. The previous results about the relatively new approach in compatibilizing the immiscible blends by addition the selected stearate pre-treated CaCO3 nanofilers and its specific surface effects on polymer matrices in blends (SAN/EPDM, PP/PVC) will be also presented. The changes in surface functionality of calcium carbonate nanoparticles by the specific surface pre-treatments, for example with silanes, resulted in higher work of adhesion with PU matrix due to the increased interactions at the interface. On the other hand some pre-treatments of calcium carbonate by irradiation in a presence of monomer and/or with stearic acid might lowered the interactions with PVAc matrix. Significantly higher coefficient of interactions in nanocomposites vs. microcomposites was indication of the mechanical properties improvements. The homogeneous morphology without agglomerates was found as important factor for the increased interactions with significant amount of immobilized polymer chains in the interfacial area. We found that in situ technology of preparation the PVAc+CaCO3 nanocomposites in comparison to the mixing procedure result in the more homogeneous morphology and significantly improved properties even with a smaller amount of nanofillers.

interface; adhesion parameters; coefficient of interactions; nanoparticles; composites; blends

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