短繊維強化ポリエチレンテレフタレートの強化機構に対する繊維径の効果

Abstract

Strengthening mechanisms of injection-molded, short-glass-fiber-reinforced polyethylene terephthalate) under uniaxial tension were studied with particular attention to the effect of fiber diameter (d=6, 10, 16, 23μm). Effects of fiber surface treatment were also investigated. Young's modulus was well described by the Cox model considering the fiber aspect ratio and the normalized center-to-center distance between fibers. Tensile strength was quantitatively analyzed on a presently modified version of Kelly's model. The version took into account the strength increase with increasing fiber lateral surface area as well as the strength decrease caused by failure occurrence. It was found that the version accounted for the obtained strength data rather well. Furthermore it was shown that failure strain and total strain energy were partly affected by the fiber lateral surface area. In conclusion, fiber aspect ratio, normalized center-to-center distance between fibers and fiber lateral surface area were significantly influenced by the change in fiber diameters and fiber surface treatment during injection molding. These values, rather than the fiber diameter itself, considerably affected strengthening mechanisms in short fiber reinforced thermoplastics.