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

Chihaoui Belgacem,Sami Boufi,Francesc Xavier Espinach,Marc Delgado-Aguilar,Quim Tarres,Pere Mutjé

doi:10.3390/polym12061423

Abstract

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.

Highlights

Natural fiber-reinforced composites are a form of composite produced by means of blending woody and/or non-woody biomass fibers with a matrix, usually polyethylene or polypropylene, usually at ratios of between 20 and 60 wt %
Woody and non-woody fibers remain the main source for the production of natural fiber-reinforced composites, in practice, any resource of lignocellulosic fibers could be used for this purpose, such as agricultural crop residue, side streams from agricultural and industrial activities or annual plants
As explained in the previous section, 40 wt % reinforced composites were prepared from each type of date palm fibers (DPF) (DPF-D, DPF-NaOH and DPF-E) using 5 wt % of maleated polypropylene (MAPP) as a coupling agent

Summary

Introduction

Natural fiber-reinforced composites are a form of composite produced by means of blending woody and/or non-woody biomass fibers with a matrix, usually polyethylene or polypropylene, usually at ratios of between 20 and 60 wt %. Examples of applications include outdoor and indoor wood-like furniture, decking and boardwalks, flooring, window and door profiles proof, outdoor building trims, interface elements in construction and automotive interior parts, among others [1] The use of such composites offers numerous advantages, such as (i) the substitution of a large fraction of petrochemical materials with bio-based materials deriving from biomass, (ii) the reduction of landfilled waste, (iii) high durability with high resistance to fading, staining and scratching, (iv) low maintenance requirements with good dimensional stability, (v) aesthetic characteristics of wood, and (vi) good thermal and acoustic insulating properties [2,3]. Apart from date fruit, which is highly nutritional, date trees produce large quantities of agricultural waste and side streams stemming from the pruning of date palm, which roughly accounts for 50 kg per year [4]. This pruning is needed to remove old, dead or broken leaves and improves the quality of the fruit

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Results

Conclusion