Development of Bio-Based Foams for Sustainable Building Materials

Bio-based foams are an environmentally friendly substitute for conventional foams, which are made by replacing petroleum-based polyols with renewable, bio-based polyols. These bio-based polyols can be derived from various natural sources, including lignin, castor oil, palm oil, soybean oil, tannin, coconut, and various sugar alcohols. Based on the literature, lignin, castor oil, and tannin have been identified as strong candidates for achieving the desired properties for bio-based foams. Lignin, a significant by-product of the pulp and paper industry, can be modified to produce polyols suitable for rigid polyurethane foam production. Castor oil, widely used in industry, naturally contains hydroxyl groups contributing to foam reactivity and flexibility. Tannin, a polyphenolic compound found in plants, can also enhance bio-based foams mechanical and thermal properties. Other sources such as palm oil, soybean oil, coconut oil, sorbitol, and mannitol, provide alternatives based on their respective hydroxyl contents, offering versatility for polyol replacement in foam synthesis. Upon reviewing these materials, lignin, castor oil, and tannin emerge as the most promising candidates for polyol use in producing bio-based foams. These materials provide a sustainable solution and demonstrate excellent properties that fulfil the requirements for thermal insulation, mechanical strength, and eco-friendliness in various applications.