Lizé-Mari Ferreira

Green composites from castor oil and renewable reinforcing materials
Resource and environmental pressures have led a drive towards a green economy of product manufacture. This entails, where possible, the use of renewable feedstocks, low energy production processes and post-use re-use, recycling, repurposing and environmentally friendly disposal. This has been encapsulated in a number of directives such as those in the European Union for an increase of renewable content in final products such as motor vehicles.

This has necessitated studies into the replacement of conventional materials, e.g., metals and petrochemical-derived polymers by composites made from renewable and/or recycled feedstock.

In this study green composites based on a castor oil-derived matrix and renewable reinforcing materials such as wood flour and chips, corn stover and sugar cane bagasse will be produced.

Castor oil consists of unsaturated fatty acid triglycerides. The oil is bio-decomposable. What makes castor oil triglycerides special, is that they contain hydroxyl groups along the fatty acid backbones. This allows the fatty acid to be crosslinked into a thermoset structure, ideal for composites, by condensation, addition or ROMP polymerisation.

This study will compare conventional epoxy thermoset matrix renewable composites with renewable matrices based on castor oil. Castor oil polyurethanes have a long history. In this study, however, it is proposed to move away from polyurethanes to maleic acid and maleic anhydride condensation polymers.