Comparative Analysis of the Coffee and Cocoa Industry By-Products on the Performance of Polyethylene-Based Composites

Abstract

The application of plant-based by-products from the food industry as minimally processed functional fillers for polymeric composites is an increasingly popular trend among researchers and manufacturers. While minimizing the preprocessing of lignocellulosic fillers leads to an increase in the sustainability of the overall composite and a decrease of the carbon footprint, filler modification is usually indispensable to obtaining sufficient mechanical and thermomechanical properties of a composite. The goal of the presented study was a comprehensive analysis of the structure, mechanical and thermal performance of polyethylene-based (PE) composites with spent coffee grounds (FK) and cocoa husks (KK). Differential scanning calorimetry (DSC) measurements showed the antioxidant activity of both fillers, extending the oxidation induction time by 100% (54 min) compared to pure PE (20 min). Composites with up to 5 wt% of the filler were characterized by low porosity (0.5%) and revealed tensile strength of about 20 MPa, which is comparable with the results of unmodified PE. However, the materials' ductility was affected, reducing elongation at break and tensile toughness by two orders of magnitude. In order to quantify changes in adhesion at the interface, a comprehensive analysis of thermomechanical parameters based on dynamic mechanical analysis (DMA) was carried out, including the assessment of interactions on the interface of the composite caused by the increase in free volume inside composites' structure. Graphical Abstract

Uniaxial Rotational Molding of Bio-Based Low-Density Polyethylene Filled with Black Tea Waste

“…For example, adding coffee grounds and coffee by-product products into the polyethylene matrix increases the oxygen induction time (OIT) [ 24 ]. The same good properties have HDPE filled with cocoa husk [ 25 ]. The industry by-products rich in antioxidants also contain cellulose, which is susceptible to thermal degradation.…”

Intrinsic Response of surface modified Calotropis Gigantea Fiber and Nelumbo nucifera filler hybrid composite

“…The form, size, and percentage of filler, including the extraction process and treatment methods used on fillers, all have a substantial impact on the efficacy of binding inside interfaces and the characteristics of composite materials [17,18]. Dynamic Mechanical Analysis (DMA) is an extensively used approach to ascertaining the temperature-dependent variations in the viscoelastic characteristics of composite materials [19]. This research paper aims to investigate the fabrication of polymer composites using alkali-treated and microwaved Calotropis gigantea (CMTCG) fiber mat and incorporating Nelumbo Nucifera filler.…”

Linear low‐density polyethylene modified with d‐limonene/β‐cyclodextrin inclusion complex: Antimicrobial composite for active food packaging

“…Due to the fact that fossil raw materials are non‐renewable, vast efforts are made to limit their usage or to reduce their environmental impact 3–5 . One approach widely exploited in the literature, mostly in the context of food packaging, is represented by the introduction of natural modifiers, like cellulose, starch, calcium carbonate, etc 6–11 . When such modifiers are able to extend food shelf life, for example, by providing active barrier against outer reagents, or other features related with food preservation, an active packaging is developed 12 .…”

“…[3][4][5] One approach widely exploited in the literature, mostly in the context of food packaging, is represented by the introduction of natural modifiers, like cellulose, starch, calcium carbonate, etc. [6][7][8][9][10][11] When such modifiers are able to extend food shelf life, for example, by providing active barrier against outer reagents, or other features related with food preservation, an active packaging is developed. 12 The latter can be designed in the shape of bags, trays, films, or containers, 13,14 which are produced via standard manufacturing methods such as injection molding, extrusion, or thermoforming.…”