Optimisation of Bio-polyol Production from Cassava Residue Using Ethylene Glycol as the Liquefaction Reagent

Cassava residue was liquefied by using ethylene glycol (EG), ethylene carbonate, propylene carbonate and polyethylene glycol (molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130–170 °C with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1 ( w/w ), the liquefaction temperature was 150 °C, the liquefaction time was 3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.