Preparation and characterization of biopolyol via liquefaction of rice straw

Abstract

Biopolyols were prepared by the liquefaction of rice straw under the mild condition. The optimum liquefaction effect was obtained at 5 : 1 volume ratio of PEG400 to DEG, 4 : 1 liquid–solid ratio, H₂SO₄ 3%, time 2.5 h, and reaction temperature120°C. Products were characterized by FTIR and gel permeation chromatograms (GPC) measurements. The hydroxyl value and weight-average molecular weight of the biopolyol produced based on the above optimal conditions were 260 mg KOH/g polyol and 420 g mol^–1, respectively. Biopolyol obtained is suitable for the preparation of rigid polyurethane foam. This study has certain significance for the high added value use of rice straw and reducing the production cost and improvement biodegradability of polyurethane foams.