Thermo-mechanical property enhancement of rigid polyurethane foam composite using low-cost, environment-friendly fly ash over silica particles

Abstract

Low-cost and environment-friendly fly ash particles and silica particles were used as additives in the rigid polyurethane foam composite. The usage of fly ash will decrease the need for its handling and exposure to the environment. FTIR spectra show the absence of hydrogen-bonded urea which indicates no aggregation of hard urea domains in the soft polyurethane matrix after the addition of silica/fly ash. The composite loaded with a 20-weight percentage of fly ash had the highest glass transition temperature. At the 10-weight percentage of the additive, the gross calorific value in the fly ash-loaded composite decreased by 12% when compared with the composite loaded with silica. The introduction of fly ash into the foam composite up to a certain weight percentage (10 wt%) enhanced the compressive strength of the rigid polyurethane foam composite. The percolate particle concentration was at 10 weight percentage of the additive. The addition of fly ash increased the compressive strength up to 21% compared to the foam composite loaded with silica. The addition of fly ash in the foam composite resulted in a decrease of water absorption up to 23% in comparison to the composite loaded with silica. Hence, low-cost and environment-friendly fly ash is a suitable additive that can be loaded into rigid polyurethane foams for superior enhancement in mechanical and thermal properties.