Continuous unidirectional palmyra palm leaf stalk fiber/glass-polyester composites: static and dynamic mechanical properties

Various chemical treatments such as mercerization (alkali treatment), permanganate treatment, and benzoyl chloride treatment were performed on palmyra palm leaf stalk fibers. Composites were fabricated by hand layup method followed by compression molding process using unsaturated polyester as matrix. Two types of composites were fabricated, one by using treated continuous palmyra palm leaf stalk fibers and other by hybridizing nonwoven glass fiber mat and alkali treated continuous palmyra palm leaf stalk fibers with bilayer arrangement. In both the cases palmyra palm leaf stalk fiber is laid unidirectionally for composite fabrication. The composites were tested for its tensile, flexural, impact, and dynamic mechanical properties. There was an increase of 33% in tensile, 55% in flexural, and 50% in impact strength for benzoyl, permanganate, and alkali treated composites, respectively, compared to untreated fiber composites. But all the treated fiber composites did not show much variation in properties. Hybridization resulted in 54, 36, and 58% improvement in tensile, flexural, and impact properties, respectively, in comparison to unhybridized treated unidirectional palmyra palm leaf stalk fiber composites. Reinforcement of alkali treated fibers and hybridization of glass fibers enhanced the loss and storage modulus of the composites, increased glass transition temperature (T-g), and also reduced the tan peak. A positive shift in tan was also evident for all the composites.