Progress and challenges in sustainability, compatibility, and production of eco‐composites: A state‐of‐art review

Abstract

Owing to economic and environmental benefits, new generations of materials/commodities follow “from waste to wealth” strategy. Recently, there has been a huge upsurge in research on the development of eco‐composites using recycled plastic polymers and agro‐residues because the eco‐composites satisfy the stringent environment regulations and are cost‐effective. Herein, we present a detailed review on the potential use of several types of natural fillers as an efficient reinforcement for recycled plastic polymers. In particular, the characterization of different categories of eco‐composites according to their morphological, physical, thermal, and mechanical properties is extensively reviewed and their results are analyzed, compared, and highlighted. Furthermore, a framework to produce functional eco‐composites, which includes functionalization of ingredients, critical issues on microstructural parameters, processing, and fabrication methods, is outlined and supported with sufficient data from the literature. Finally, the review outlines the emerging challenges and future prospects of eco‐composites to be addressed by interested researchers to bridge the gap between research and commercialization of such a class of material. Overall, the acquired knowledge will guide researchers, scientists, and manufacturers to plan, select, and develop various forms of eco‐composites with enhanced properties and optimized production processes.

New Synthesis Routes toward Improvement of Natural Filler/Synthetic Polymer Interfacial Crosslinking

“…Because of the slow growth rate of trees and the scarcity of forest resources, alternative forms of lignocellulosic materials are being introduced to replace traditional wood flour fillers for emerging applications [ 3 , 4 , 5 ]. In general, a lignocellulosic biomass is a form of fiber or flour that is utilized as a reinforcing element in a polymer [ 6 , 7 ]. Natural fibers such as kenaf, flax sisal, and bamboo offer major advantages over their synthetic counterparts, such as carbon fillers and glass fillers, due to their low density, low cost, and ability to reduce mechanical wear during processing [ 8 ].…”

Eco-Composites from Silkworm Meal and Polycaprolactone: Effect of Formulation and Processing Conditions

“…However, research on its potential use as a raw material in the development of green plastics, taking advantage of its good biodegradability, remains really scarce [21]. Enhancing the use and the performance of bio-based products could lead to a lighter environmental imprint, which diminishes the environmental footprint of synthetic plastics [22]. Thus, the use of silkworm meal in high-value applications (i.e., bioplastics) together with the promotion of green materials has been the driving force of the present manuscript.…”

“…Some pieces of research have developed biocomposites from the combination of industrial by-products and petrochemical polymers [26]. Thus, these materials could enhance sustainability, durability, and cost-effectiveness [22]. Among the latter ones, biocomposites have been developed by combining polycaprolactone (PCL), which is a biodegradable polyester that shows appropriate mechanical properties [27,28], together with some protein-rich by-products, such as rapeseed [29,30].…”

Chemical Treatment of Bio-Derived Industrial Waste Filled Recycled Low-Density Polyethylene: A Comparative Evaluation

“…The chemical treatment of fibers includes leaching out amorphous-nanocrystalline-biomass materials and removal of surface impurities and other substances. Therefore, the treated fillers reinforce the polymers by functioning as load-carrying elements owing to the improved filler-polymer compatibility, which provides strength and rigidity to the produced biocomposites [24,25]. Such treatments roughen the surface of the natural filler, and the removal of surface impurities promotes better filler-polymer interfacial compatibility and bonding, thus improving the overall performance of the produced biocomposites [26].…”