By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood-Polymer Composites.

Aleksander Hejna,Błażej Chmielnicki,Paulina Kosmela,Jerzy Korol,Anton Kuzmin,Arkadiusz Kulawik,Adam Piasecki

doi:10.3390/polym13060893

Abstract

The present paper describes the application of two types of food-industry by-products, brewers’ spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood–polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput. Replacement of WF with BSG and ŁK improved the ductility of composites, which affected their strength however. Such an effect was attributed to the differences in chemical composition of fillers, particularly the presence of proteins and lipids, which acted as plasticizers. Composites containing food-industry by-products were also characterized by the lower thermal stability compared to conventional WF. Nevertheless, the onset of decomposition exceeding 215 °C guarantees a safe processing window for polyethylene-based materials.

Highlights

One of the environmentally friendly trends in polymer technology is incorporating byproducts from various branches of industry as raw materials or intermediates in different processes
The use of wood flour often causes the reduction of high-density polyethylene flowability, which was observed by de Carvalho et al [27] and Santi et al [28]
We aimed to investigate the impact of conventional beech woodflour replacement with the two types of food-industry by-products on polyethylene-based composites’ processing and performance

Summary

Introduction

One of the environmentally friendly trends in polymer technology is incorporating byproducts from various branches of industry as raw materials or intermediates in different processes. The food industry should be considered a sector which can significantly contribute due to the enormous amounts of generated waste [1]. Around 1.6 billion tons of “primary product equivalents” is wasted each year globally [2]. Food waste is mainly subjected to fermentation and used to produce biogas. Such a solution enables the partial energy recovery but does not utilize the full potential of compounds present in these materials. It is vital to look for the possibilities for, mostly, reduction of the number of generated by-products as well as their utilization

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