Mechanical characterization of water hyacinth reinforced polypropylene composites

Abstract

At present, natural fiber reinforced polymer matrix composites have received wide attention of the researchers from all over the world because of their outstanding advantages of environment friendliness, biodegradability, recyclability, costeffectiveness, and comparable physico-mechanical properties. Among various natural fibers easily available to human beings, water hyacinth (WH) is one of the cheapest fibers which have not been systematically explored so far, to the knowledge of the author, as reinforcing materials of composites. The present study focuses on the manufacturing of WH fiber reinforced polypropylene (PP) composites with a view to investigating and evaluating their physico-mechanical and thermal properties. The WH fibers and PP were melt-mixed with a single screw extruder. This mixture was used to manufacture composites with an injection molding machine. Various mechanical properties such as tensile strength and stiffness, flexural strength and stiffness, and Charpy impact strength were measured by standard procedures and results were analyzed. Water absorption property was evaluated for 24 hours immersion in distilled water. Thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and derivative thermal gravimetric (DTG) analyses were carried out in order to evaluate the thermal properties of composites. Scanning electronic microscopic (SEM) images were analyzed to understand the interfacial bonding between WH fibers and PP matrix for both the raw and chemically treated fibers. Fourier transform infrared ray (FTIR) analysis was carried out to see the effect of chemical treatment on the change of molecular structures (hydrophilic to hydrophobic) of WH fibers. It was found that all the mechanical properties except tensile strength were satisfactorily improved for chemically treated WH-PP composites in comparison with those of raw WH-PP composites. Also, thermal stability of the chemically treated WHPP composites was much better than those of raw WH-PP composites. However, water absorption property was almost the same for both the chemically treated and raw WHPP composites. Further, the water absorption increases with the increase of fiber loading while the mechanical properties except tensile strength were improved with the increase of fiber loading.