Preparation and characterization of natural composite based on plasticized potato starch and date palm fibers

Abstract

Natural composites have become a necessity with which we should not dispense since they will become the solution and alternative for many traditional polymers that are made of petroleum resources. By adopting natural, biodegradable polymers, we will definitely contribute in preserving the environment as well as the fossil fuel which is on its way to depletion in the coming decades. This work is aimed at the characterization of natural composite based on glycerol plasticized potato starch reinforced with date palm fibers. Potato starch is plasticized with high purity glycerol and compression molded. Various compositions of date palm fibers (3.5%, 6.9%, 10%, 12.9%, 15.6%, 18.1%, and 22.8% by volume) were used out on the same matrix formulation. The average diameter of date palm fibers used is 0.3 mm and their average length is 5mm. Date palm fibers are tested using tension test to determine their ultimate tensile strength. The properties of this potato starch/date palm fibers composite material are analyzed. Mechanical properties (tensile and 3-points bending tests) are used to examine the maximum stress the composite can endure before it fails as well as to determine the effect of different date palm fibers volume fractions on the strength, modulus of elasticity, and strain of the composite material. X-Ray diffraction (XRD) is used as well to determine the change in the crystallinity of potato starch before and after processing as well as its crystallinity before and after adding date palm fibers. The morphology of the thermoplastic matrix before and after adding date palm fibers (DPF) is analyzed using scanning electron microscopy. The tensile strength of the composite increased with increasing fiber content up to 22.8% by volume. Values for tensile strength and Young's modulus increased from 0.975 MPa and 40 MPa, respectively, for the neat matrix and reached a value of 6.67MPa, and 800 MPa for the composite with 22.8% by volume. Crystallinity increased from 27.16% for thermoplastic starch to 36.03% for the 22.8% composite. Electrical resistivity experienced an increase from 0.48 MΩ for the plasticized matrix to reach 3.26 MΩ for the composite containing 22.8% by volume of DPFs. Anticipated applications for this composite are automotive industry, construction industry, and food packaging.