Synthesis of lignin-based polyurethane foam extracted from black liquor waste

Polyurethane foam is a cushion-shaped polymer which application is commonly used for the vehicle, furniture, and thermal insulation. However, the composition still contains non-renewable petroleum-based polyol. Therefore, a substitute for polyol is needed to solve this problem. One of the alternatives to solve this problem is lignin. Lignin is the second most abundant natural polymers in the world with a growth rate of 3 x 109 tons/year. This research aims to study the effects of substituting polyol with lignin to produce polyurethane foam. Polyurethane foam was prepared by mixing lignin and isocyanate with a concentration of 5%, 10%, 20%, 30% and 40% (w/w). The properties of lignin-based polyurethane foams such as blowability, density, and degradation rate were measured and tested; observation of the morphology was conducted by using an optical microscope. The results show that lignin can be used as a substitute for polyol to produce polyurethane foam. Lignin-based polyurethane foam has the highest blowability of 119.1% and the lowest density of 0.4123 gr/cm3.