Mechanical and Morphological Properties of Chemically Treated Coir-Filled Polypropylene Composites

Abstract

In the present work, coir was chemically treated first with sodium perchlorate and then with 2,4-dinitrophenyl hydrazine (DNPH) to improve the mechanical properties of the coir−PP composites. Untreated, oxidized, and DNPH-treated coir samples at different mixing ratios were utilized to prepare the composites. Mechanical properties of the composites prepared from both perchlorate and DNPH-treated coir were found to be better than those of untreated ones. The tensile strengths of both untreated and treated coir−PP composites decreased with an increase in fiber content. However, the values were found to be higher than those of corresponding values of untreated ones. Treated coir−PP composites were found to absorb a lower amount of water than the untreated ones. To understand why the mechanical properties of composites prepared under different conditions of coir were different, surface morphologies of the tensile fractured surfaces of the specimens were recorded using scanning electron microscopy (SEM). The SEM images clearly revealed that there were fewer fiber agglomerations, microvoids, and fiber pull out traces in both perchorate and DNPH-treated coir−PP composite than in the untreated one, indicating that better distribution of the fiber into the matrix as well as stronger fiber matrix interfacial adhesion occurred upon treatment of coir.