The effect of low temperature air plasma treatment on the physico-chemical properties of kaolinite/polyethylene composites was studied. Moreover, the kaolin powder was treated with (3-aminopropyl)triethoxysilane as a coupling agent to improve the interfacial adhesion between powder filler and polymer matrix. The modification of the kaolin resulted in a notable improvement in the mechanical strength and elastic modulus of filled polyethylene composites, compared to the virgin polymers. Observed improvement of the tensile strength became more marked as the filler loading increased, indicating an improved degree of filler/matrix interaction. Simultaneously the improvement of the fracture toughness of prepared HDPE and LLDPE kaolinite composites was confirmed. Moreover, the morphology of the grains distribution and tensile fracture surface was examined by electron microscopy confirming excellent distribution of the filler in the polymer matrix.
Main aim of this study was focused on characterization of the effect of microwave air plasma treatment on wettability of synthetic polymer surfaces. Wettability of solid polymer surfaces polyethylene, polypropylene, polystyrene (PE, PP, PS) was followed as a function of plasma treatment time. For evaluation the equilibrium contact angles of wetting as well as dynamic contact angles of wetting were determined by means of sessile drop and Wilhelmy plate methods. Free surface energy (SFE) of studied samples were calculated from the experimentally determined contact angles using Fowkes and van Oss, Chaudhury and Good (vOCG) approaches. It was found that with prolonged treatment time the total surface free energy of PE was two times increased from 23 mJ/m<sup>2</sup> to 45 mJ/m<sup>2</sup> after 360 s plasma treatment time (calculated for W and EG as wetting liquids). Similar effect was found for all studied polymers. With respect to the dispersive and polar components of the total surface free energy the vigorous effect was found for polar component, for which it was increased from 7 mJ/m<sup>2</sup> to 20 mJ/m<sup>2</sup>
It was found in this study that air plasma treatment of particular kaolinite has led to the change of its wettability. This was reflected in the decreased values of water contact angles of wetting. There were determined yield locus and flow function dependencies at different stress levels for virgin and different time plasma treated samples (flow index - ffc, effective angle of internal friction - phie, unconfined yield strength - sigmac). It was found that by plasma treatment the character of the flow was shifting from region of very cohesive (ffc = 2.39) to the cohesive (ffc = 3.19). For untreated samples effective angle of internal friction was decreased with increasing applied consolidation stress, while for plasma treated kaolinite it was increased.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.