Molecular Design of Sugar-Based Polyurethanes

Polyurethane (PUs) are present in many aspects of everyday lives such as the rigid foam insulation panel in construction, seat cushion in automotive and elastomeric materials in medical industries. Conventional PUs are made from petrochemical based starting materials which raised severe health and environmental concerns. The substitution of petro-based polyols with carbohydrate polyols have shown to improve biodegradability and mechanical properties of PUs. Reaction pathways were examined with density functional theory to design novel environmental friendly polyurethanes. Based on the calculated thermodynamic properties, the reactivity of sugars towards isocyanates was compared. Fructose was found to be the most reactive as the corresponding fructose-isocyanate reaction has the lowest energy barrier of 135.6 kJ/mol. Therefore, the results obtained have encouraged the synthesis of fructose-based polyurethane foam. The synthesis was successful, and the produced fully fructose-based foam was stable with minimal sign of shrinkage.