Replacement of petroleum-derived diols by sustainable biopolyols in one component polyurethane foams

Abstract

This work reports on the development of eco-innovative and high performance one component polyurethane foams, originated from biopolyols, which were obtained from liquefaction of biomass, industry by-products, namely cork powder and eucalyptus bark. This effort consists of a cleaner production method to enable more sustainable materials and industry by-products valorisation, but also a reduction of the dependency on fossil oil derivatives. Low-value industrial cork powder and eucalyptus bark shreds were successfully liquefied into polyols, by a process based on acid-catalysed liquefaction, at atmospheric pressure, with conversion ratios up to 79%. The obtained biopolyols exhibited low acid values (1 mg KOH/g) and relatively high hydroxyl numbers (197–272 mg KOH/g) and were introduced into one component polyurethane formulations, fully replacing the petroleum-derived polyether and polyester diols in the formulation. The resultant rigid polyurethane foams exhibited a high output (16 g/s) and acceptable physical quality, assessed by optical and scanning electron microscopy. Their chemical structure, mechanical and thermal properties were evaluated through Fourier Transformed infrared spectroscopy, compression mechanical testing and thermogravimetric analysis, respectively.