Effects of polyhedral oligomeric silsesquioxane coatings on the interface and impact properties of carbon-fiber/polyarylacetylene composites

Two kinds of polyhedral oligomeric silsesquioxane (POSS) coatings were used for the modification of the interface in carbon fiber (CF) reinforced polyarylacetylene (PAA) matrix composites. The effects of the organic-inorganic hybrid POSS coatings on the properties of the composites were studied with short-beam-bending, microde-bonding, and impact tests. The interlaminar shear strength and interfacial shear strength showed that the POSS coatings resulted in an interfacial property improvement for the CF/PAA composites in comparison with the untreated ones. The impact-test results implied that the impact properties of the POSS-coating-treated composites were improved. The stiffness of the interface created by the POSS coatings was larger than that of the fiber and matrix in the CF/PAA composites according to the force-modulation-mode atomic force microscopy test results. The rigid POSS interlayer in the composites enhanced the interfacial mechanical properties with a simultaneous improvement of the impact properties; this was an interesting phenomenon in the composite-interface modification. (c) 2006 Wiley Periodicals, Inc.