The effect of the concentration of the sizing agent on performances of carbon fiber and carbon fiber composites has been investigated. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were applied to characterize carbon fiber surface topographies. At the same time, the single fiber strengths and Weibull distribution were also studied. The interlaminar shear strength and hygrothermal ageing test have been used to study the effect of fiber coatings on the interface of the composites. The analysis of the results shows that the sizing level is essential for improving the surface of carbon fibers and its composite performance. Different concentrations of the sizing agent have different contributions to the wetting performance of carbon fibers. Among the three concentrations of sizing agent studied (1 wt %, 1.5 wt %, and 2 wt %), the optimal sizing level is 1.5 wt %. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 125:425–432, 2011

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ABSTRACT:The polymer, Hydrogenated Nitrile-Butadiene Rubber (HNBR) was melt compounded with organophilic montmorillonite (OMMT). The dispersion of the OMMT in the HNBR matrix was characterized by X-ray diffraction (XRD), which indicated that at the temperature of 100 C, the organoclay belong to the exfoliated and interlayer structure. The effect of sulfur on the dispersion of OMMT in the polymer matrix was also studied. The vulcanization changed the dispersion of OMMT in polymer matrix greatly and the basal spacing of clay layers is decreased after vulcanization. The mechanical properties, Akron abrasion and the crude oil medium aging-resistant of HNBR nanocomposites were examined as a function of the OMMT content in the matrix of polymer. The results of the test show remarkable improvement in tensile strength, tear strength, aging-resistant, and hardness of HNBR nanocomposites than that of unfilled HNBR. It is obvious that the 10 phr of OMMT filled nanocomposites have the best mechanical properties.

The role of the type of layered silicate platelets, OMMT and rectorite on the mechanical properties, aging resistance and oxygen permeation properties of HNBR/layered silicate nanocomposites was investigated. The effect of peroxide vulcanising agent on the dispersion of layered silicate in the HNBR matrix was also studied. HNBR was mechanically mixed with layered silicate via melt blending method. The results of the test show remarkable improvement in tensile strength, tear strength, aging resistance and oxygen permeation properties of HNBR nanocomposites than that of unfilled HNBR. It is obvious that the OMMT filled nanocomposites have far better properties than that of rectorite filled HNBR.