Mechanical properties of natural fiber reinforced polymer (NFRP) composites using anahaw (Saribus rotundifolius) fibers treated with sodium alginate

Natural fiber reinforced polymer (NFRP) composites have been a focus of various research projects because of their advantages compared to traditional fiber reinforced plastics. In this study, Anahaw (Saribus rotundifolius) was used as fiber source because it is abundant in the Philippines. The fibers were treated by immersing in a sodium alginate solution and then in a calcium chloride solution. The treated fibers were used to reinforce the orthophthalic unsaturated polyester. Mechanical properties were tested using a universal testing machine (UTM) and the fracture surfaces were characterized using a scanning electron microscope (SEM). Sodium alginate treatment resulted in higher tensile and flexural strengths of the composites as compared to those reinforced with untreated fibers. On the other hand, the sodium alginate treatment was not able to show any improvement on the wet mechanical properties of the material. The increase in fiber load was also found to increase the stiffness of the composites. The measured stiffness and modulus of the treated Anahaw fiber-reinforced composite was found to be comparable to those of commercially available particle boards and fiber boards.   Key words: Natural fiber reinforced polymer (NFRP), composite, sodium alginate, anahaw, polymer.