Mechanical properties of abaca fiber reinforced polypropylene composites: Effect of chemical treatment by benzenediazonium chloride

Untreated abaca fibers and benzenediazonium chloride treated abaca strands were employed as reinforcements for fabricating polypropylene composites by injection molding method. Various composites were fabricated with different fiber loadings of 30%, 35%, 40%, 45% and 50% with and without coupling agents. Abaca composites without coupling agents with 40% fiber loadings were found to have optimum properties when mechanical characterization was done and the investigation also revealed that untreated and treated composites with coupling agents were found to have improved tensile strength, flexural strength and impact strength when correlated to composites without coupling agents. Among various surface modifications performed, benzenediazonium chloride treated abaca strands reinforced polypropylene composites with coupling agents showed superior properties. For composites including coupling agents, surge in tensile strength and flexural strength was observed with hike in fiber content up to 50% whereas optimum impact properties were shown at 40% fiber loading. Between untreated composites with coupling agent and without coupling agent, composites with coupling agent showed 77.50% hike in tensile strength for 50% fiber loading. Benzenediazonium chloride treated composites with coupling agent showed 70.07% increase in tensile strength when compared to benzenediazonium chloride treated composites without coupling agent for 50% fiber loading. Untreated composites with coupling agent showed 64.91% increase in flexural strength when compared to untreated composites without coupling agent for 50% fiber loading. Benzenediazonium chloride treated composites with coupling agent showed 36.84% increase in flexural strength when compared to benzenediazonium chloride treated composites without coupling agent for 50% fiber loading. However, in case of impact strength, addition of coupling agent increased the impact strength up to 35% fiber loading and beyond 35% fiber loading addition of coupling agent decreased the impact strength. Untreated composites with coupling agent showed 3.53% decrease in impact strength when compared to untreated composites without coupling agent for 40% fiber loading. Benzenediazonium chloride treated composites with coupling agent showed 6.59% decrease in impact strength when compared to benzenediazonium chloride treated composites without coupling agent for 40% fiber loading.