High-Yield Lignocellulosic Fibers from Date Palm Biomass as Reinforcement in Polypropylene Composites: Effect of Fiber Treatment on Composite Properties

In this work, date palm waste (DPW) stemming from the annual pruning of date palm was used as reinforcing filler in polypropylene (PP) matrix at 40% w/w. Three pre-treatment routes were performed for the DPW, namely (i) defibration, (ii) soft alkali treatment, and (iii) enzymatic treatment, to obtain date palm fibers (DPF) and to investigate the effect of each process on their chemical composition, which will ultimately affect the mechanical properties of the resulting composites. The enzymatic and alkali treatment, combined with maleated polypropylene (MAPP) as a coupling agent, resulted in a composite with higher strength and stiffness than the neat PP. The differences in the reinforcing effect were explained by the change in the morphology of DPF and their chemical surface composition according to the selected treatment of DPW. Enzymatic treatment maximized the tensile strength of the compound as a consequence of an improvement in the interfacial shear strength and the intrinsic resistance of the fibers.