Influence of Fiber Orientation on the Mechanical Properties of Polyester/Jute Composites

Tensile and impact properties of compression molded unsaturated polyester/jute composites were investigated as a function of fiber content and orientation. Both unidirectional fiber composites with 0-50% weight fiber content and a randomly distributed short-fiber composite with 30% w/w were manufactured. The unidirectional composites were tested along and transversally to the fiber axis. Higher values for all mechanical properties were obtained when long-fiber oriented composites were tested along the fiber axis, even at low fiber content (10% w/w). The tensile behavior of the unidirectional composites qualitatively followed the theoretical isostrain and isostress behaviors, when the tests were conducted along and perpendicular to the fiber axis, respectively. The tensile properties of the composites tested perpendicular to the fiber were dominated by the strain at the fiber-matrix interface. Properties for randomly distributed short-fiber composites were found to be intermediate between those obtained with long-fiber oriented composites with the same fiber load tested along and across the fiber direction.