Bio-Polyethylene-Based Composites Reinforced with Alkali and Palmitoyl Chloride-Treated Coffee Silverskin

Abstract

This work investigates the feasibility of using coffee silverskin (CSS) as a reinforcing agent in biobased polyethylene (BioPE) composites, by adding it in bulk and thin film samples. The effect of two different treatments, alkali bleaching (CSS_A) and esterification with palmitoyl chloride (CSS_P), on mechanical, thermal, morphological and water absorption behavior of produced materials at different CSS loading (10, 20 and 30 wt %) was investigated. A reactive graft copolymerization of BioPE with maleic anhydride was considered in the case of alkali treated CSS. It was found that, when introduced in bulk samples, improvement in the elastic modulus and a reduction in strain at maximum stress were observed with the increase in CSS fraction for the untreated and treated CSS composites, while the low aspect ratio of the CSS particles and their poor adhesion with the polymeric matrix were responsible for reduced ductility in films, decreasing crystallinity values and reduction of elastic moduli. When CSS_A and CSS_P are introduced in the matrix, a substantial reduction in the water uptake is also obtained in films, mainly due to presence of maleated PE, that builds up some interactions to eliminate the amounts of OH groups and hydrophobized CSS, due to the weakened absorption capacity of the functionalized CSS.

Torrefaction of Coffee Husk Flour for the Development of Injection-Molded Green Composite Pieces of Polylactide with High Sustainability

“…Some previous studies have reported similar mechanical properties of green composites based on coffee waste derived fillers. For instance, Dominici et al [58] showed a worsening of tensile strength and ductility when CSS was incorporated into bio-based high-density polyethylene (bio-HDPE). The described decrease of the mechanical properties was ascribed to the low aspect ratio of the CSS particles as well as their poor adhesion to the biopolymer matrix.…”

Fabrication and Characterization of Microcellular Polyurethane Sisal Biocomposites

“…Polyurethane is one of the polymers that play an important role in our life [11][12][13]. It plays a part in many industries; from footwear to ship-building, and it can be found in a constantly increasing variety of forms [14][15][16][17]. Automotive companies have focused recently on several polymer biocomposite materials in order to obtain materials with vibration damping and sound absorption properties in addition to light weight for reduced fuel consumption [18].…”

Coffee By-Products and Their Suitability for Developing Active Food Packaging Materials

“…CH [ 71 ] and SCG [ 78 ] powder can be incorporated into polypropylene (PP)-based formulations, and CS powder [ 77 ] into high-density polyethylene (HDPE)-based formulations. These composites showed increased rigidity and decreased elongation at break, due to the poor interfacial adhesion between coffee by-products and the polymeric matrices.…”