Chemical Modification Effect on the Mechanical Properties of Coir Fiber

Natural fiber has a vital role as a reinforcing agent due to its renewable, low cost, biodegradable, less abrasive and eco-friendly nature. Whereas synthetic fibers like glass, boron, carbon, metallic, ceramic and inorganic fibers are expensive and not eco-friendly. Coir is one of the natural fibers easily available in Bangladesh and cheap. It is derived from the husk of the coconut (Cocos nucifera). Coir has one of the highest concentrations of lignin, which makes it stronger. In recent years, wide range of research has been carried out on fiber reinforced polymer composites [4-13].The aim of the present research is to characterize brown single coir fiber for manufacturing polymer composites reinforced with characterized fibers. Adhesion between the fiber and polymer is one of factors affecting the strength of manufactured composites. In order to increase the adhesion, the coir fiber was chemically treated separately in single stage (with Cr2(SO4)3•12(H2O)) and double stages (with CrSO4 and NaHCO3). Both the raw and treated fibers were characterized by tensile testing, Fourier transform infrared (FTIR) spectroscopic analysis, scanning electron microscopic analysis. The result showed that the Young's modulus increased, while tensile strength and strain to failure decreased with increase in span length. Tensile properties of chemically treated coir fiber was found higher than raw coir fiber, while the double stage treated coir fiber had better mechanical properties compared to the single stage treated coir fiber. Scanning electron micrographs showed rougher surface in case of the raw coir fiber. The surface was found clean and smooth in case of the treated coir fiber. Thus the performance of coir fiber composites in industrial application can be improved by chemical treatment

Manufacturing of coir fibre-reinforced polymer composites by hot compression technique

This present chapter describes the manufacturing technique and properties of coir fibre-reinforced polypropylene composites manufactured using a hot press machine. The effects of basic chromium sulphate and sodium bicarbonate treatment on the physical and mechanical properties were also evaluated. Chemical treatment and fibre loading generally improved the mechanical properties. Five-hour basic chromium sulphate and sodium bicarbonate-treated coir-polypropylene had the best set of properties among all manufactured composites. Chemical treatment also improved water absorption characteristics. This proves that chemical treatment reduced the hydrophilicity of the coir fibre. Overall the hot compression technique was proved to be successful in manufacturing good quality coir reinforced polypropylene composites

Toward better understanding of mechanical response of fabrics under multiple combined loading modes : experimental and statistical analysis

Fabric reinforced composites are becoming among primary materials of choice in manufacturing damage tolerant aerospace, automotive, and naval architectural parts. Detailed characterization of fabric reinforcements, however, is necessary to ensure the quality of such composite part and to prevent structural failure during their service. A number of experimental studies have been dedicated in the past to characterize the deformation of fabrics under individual loading modes, such as pure uniaxial tension, pure biaxial tension and pure shear. There still exists, however, a lack of knowledge and standardization in testing and analyzing the mechanical response of fabrics under combined shear-tension loadings, both in simultaneous and sequential modes. Moreover, in reality, there are sources of uncertainties in the forming of these multi-scale fibrous materials, which often results in non-repeatable test data and causes inconsistencies for full characterization. Recognizing the above gaps, the aim of this thesis has been to design, conduct, and analyze a set of experiments for enhanced characterization of a typical glass fabric under select individual and combined shear-biaxial tension loading modes. The experimental tests were performed using a new fixture recently designed and manufactured by the Composites & Optimization Laboratory at UBC and its international partners. On the account of inherent material uncertainties, all tested deformation modes were analyzed and compared via a series of ANOVA analysis. Results showed that statistically there were significant differences between the warp and weft responses of the fabric under all the deformation modes, with weft yarns being generally stiffer. The shear-tension coupling effect in combined deformation modes yielded higher normal axial and shear forces compared to the individual deformation modes. More severe local damage zones were observed during the coupling tests. Finally, a Digital Image Correlation test was conducted to inspect wrinkling in the deformed specimens. Under a pure shear mode, some out of plane wrinkles appeared due to misalignment, whereas in the simultaneous loading condition it was nearly disappeared, thanks to the presence of fiber tension.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat