Polyurethanes with bio-based and recycled components

The topic deals with two actual environmental tasks: waste management (especially waste plastic recycling) and utilization of bio-materials (renewable resources) in polymer synthesis. The paper is focused on a preparation and a characterization of polyurethanes (PUR) combining renewable bio-based raw materials and PUR waste. A fish-oil based polyol and a castor oil are used as the bio-based raw materials. The recycled component is in the form of recycled polyols prepared by chemolysis of PUR waste. Based on the properties of the natural and the recycled polyols, final PUR materials were design as rigid PUR foams or cast PUR systems. Processing parameters as well as final thermo-mechanical properties of the prepared PUR materials were evaluated and discussed.
The results showed that the PUR system containing the fish-oil based polyols and the recycled polyols are suitable for rigid PUR foam preparation. Usually, the recycled polyols prepared by conventional glycolysis can be only added as a minor part into the PUR system. Surprisingly, a combination of the bio-polyols and the recycled polyols enables to replace a majority of petrochemical polyols in the rigid PUR foam formulation without any inferior effects on final quality of the product.
In the case of the castor oil based polyols, a preparation of cast PUR compact materials seems to be the most suitable application. Due to the high content of secondary hydroxyl groups, the castor oil based polyols are less reactive with isocyanates than the fish oil based polyols. Long aliphatic chains of the castor oil based polyols are advantageously utilized in the formulation of soft PUR floor materials.