Thermal Characterization of Polyurethane from Castor Oil Reinforced Sugarcane Straw Composites

Abstract

The development in the area of natural-fibre-reinforced composites has greatly increased in recent years. Using castor oil polyurethane (PU) as matrix for composites reinforced with lignin and cellulose from sugarcane straw is in tune with economical and environmental interests. The aim of this work was the thermal degradation study of castor oil-polyurethane composites reinforced with cellulose from sugarcane straw. For the obtainment of cellulose, sugarcane straw was pretreated by steam explosion, followed by a delignification with NaOH. For the production of the PU, the polyol (castor oil) to diisocyanate mass ratio was 1.5:1.0. Reinforcement of the matrix was done changing the concentration of cellulose fibres (5,10,15,20% w/w). Thermogravimetric analysis of the materials was carried out. The results obtained showed that the process of decomposition of the matrix occurs in one step, while for the composites it occurs in two steps. The addition of reinforcement in the matrix basically did not change the thermal stability of the composite.