Polyurethanes (PUR) combining renewable bio-based raw materials and recycled polyols were prepared and characterized. A fish oil-based polyol and a castor oil (CO) were used as the bio-based raw materials. Recycled polyols were prepared by chemical decomposition of PUR flexible foam. Based on the properties of the natural and the recycled polyols, final PUR materials were designed as rigid foams or cast systems. Processing parameters as well as final thermo-mechanical properties of the prepared materials were evaluated and discussed. The results showed that the fish oil-based recycled polyol was suitable for the preparation of the rigid PUR foam and can replace a majority of petrochemical polyols in the rigid PUR foam formulation without any detrimental effects on final quality of the product. Due to the high content of the secondary hydroxyl groups, the CO-based recycled polyol was less reactive with the isocyanates than the fish oil-based recycled polyol. Therefore, the CO-based recycled polyol was used for the preparation of the compact cast PUR materials. Long aliphatic chains in this recycled polyol could be advantageously used for the formulation of flexible PUR floorings.
Practical applications: The developed polyurethane (PUR) materials were designed for concrete final applications. The fish oil-based recycled polyol was tested for the preparation of the rigid PUR foams. The use of castor oil enabled to prepare less reactive recycled polyol and it was applied for the preparation of the compact cast PUR.