Valorization of Agricultural By-Products in Polyurethane Foams: The Role of Corn Distillers Grains in Enhancing Material Properties

Abstract The polyurethane industry is constantly looking for effective solutions which enable the production of economically advantageous and environmentally friendly materials. The design of composites with improved functional properties by addition of plant-based materials to the insulating foam is a priority. In this study, we developed biocomposites of rigid polyurethane foam containing dried Corn Distillers Grains with Solubles (DDGS). Samples containing different amounts of fillers were synthesised by free growth and using a specialized mold. The tests carried out on the obtained samples included analysis of processing parameters as well as functional, physicochemical and structural properties. The incorporation of the fillers into the polyurethane matrix resulted in an extension of the foam growth time from 107 to 128 s, increase in the free density from 66.3 to 76.3 kg/m 3 and decrease of the maximum core temperature of the foams. The mechanical properties of the majority of the studied samples were improved by adding DDGS compared to pure polyurethane foam. The tensile strength of the obtained composites ranged from 636 to 747 kPa (676 kPa was recorded for the reference foam). The obtained biocomposites exhibited high microbiological purity and low thermal conductivity in the range of 0.020–0.029 W/(m∙K), which are crucial in terms of the use of foam in the production of polyurethane hives. The use of DDGS as a filler for insulating pouring foam is an innovative solution for managing a by-product of natural origin, which is both ecologically and economically favourable for the polyurethane hive industry. Graphical Abstract