Physico-mechanical properties of typha angustata (elephant grass) fiber reinforced thermoplastic composites

Abstract

Natural fibers have been found to be excellent reinforcing materials for preparing polymer matrix-based composites. In the present study both raw and surface modified polystyrene matrix-based composites were prepared in order to explore the effect of reinforcement on the mechanical properties of the matrix. Due to increased environmental concerns natural fibers have recently attracted a great attention as reinforcement for the synthesis of fiber reinforced polymer matrix-based composites and these composites have an added advantage of being cheap, easily available, nonabrasive, easy to process, high specific strength and biodegradable in nature. Among various polymer matrices, thermoplastics are mostly used in manufacture of plastic/ wood composites. Polystyrene is one of the most important thermoplastics which is in great demand due to its transparency, fluidity and good electrical insulation properties. In the past decade, natural fiber-based composites have been utilized as door panels, seat backs, head liners, dash boards, and interior parts of car. The usage of composites is not only limited to automobile parts but it also extends to current generation military aircraft. These advance materials have the potential to contribute to aircraft development, since one-third of the structural mass of aircraft is made from fiber reinforced polymer composites. Among many natural fibers elephant grass fiber has a great prospective in the composite field, because it is cheap, available in large quantities. Its botanical name is Typha Angustata. Elephant grass (Typha Angustata) fiber is used as new natural fiber reinforcement and polystyrene as matrix. Typha Angustata fibers (TAF) were extracted and used to prepare sodium hydroxide treated and untreated TAF reinforced polystyrene composites. Composites were prepared with randomly oriented fibers with different proportions of fibers and matrix ratio. Different types of compression molded TAF- polystyrene composite were prepared using different weight percent of treated and untreated TAF with compositions 5, 15, 20, 25 and 30 wt. % in polystyrene. The composites were characterized by FT-IR and SEM analysis and their physico-mechanical and thermal properties were analyzed by tensile test, TGA and DSC analysis. Mechanical properties tensile strength, elongation at break, impact strength was measured. Improved mechanical properties were obtained for all the treated fiber reinforced composites over untreated TAF reinforced plastics composites. Scanning Electron Microscopy (SEM) were taken for all composites to investigate the interfacial adhesion and bonding between fiber and matrices. Morphological analyses showed the evidence of stronger interfacial adhesion between the fibers and matrices in the all treated TAF - polymer composites than the untreated TAF polymer composites. Thermal properties of prepared composites were examined by TGA and DSC analysis. Almost same thermal properties were obtained for all treated and untreated TAF reinforced polymer composites. Water absorption test were carried out for all composite to investigate the effect of chemical treatment on the moisture absorption properties which have direct effect on dimensional stability of the composites. According to the FTIR spectroscopic results the positive chemical treatment removed an amount of lignin and other impurities, produced dialdehyde cellulose in TAF. Water absorption tests and SEM observation results revealed that the composites with treated TAF absorbed the less water and good uniformity between fiber and matrix than composites with untreated TAF. It was found that 10 wt. % treated fiber reinforced composites have higher tensile strength than all other composites.