Castor oil is a natural polyol and widely used in many applications. Although castor oil is a renewable biobased product, its production is geographically limited to tropical regions, resulting in fluctuations in supply and price stability. This work explores the possibility of the production of castor oil alternatives from camelina oil grown in temperate regions as an industrial crop and its subsequent use in polyurethane formulations. Castor oil replacement polyols were produced from camelina oil via controlled epoxidation using in-situ generated performic acid and a subsequent hydroxylation via acid catalyzed epoxy ring opening with alcohol. The viscosity and hydroxyl functionality of camelina oil polyol was targeted to match castor oil since these parameters dictate the performance of these polyols as drop-in replacements. The reaction of camelina oil polyols and castor oil with polymeric diphenylmethane diisocyanate to produce polyurethane was studied via their rheological behavior during curing, which indicated their relative reactivities. In polyurethane applications, it was found that whilst camelina oil polyols showed lower reactivity towards isocyanates, reactivity can be readily adjusted to match castor oil by the addition of small amount of common catalysts. The thermo-mechanical properties of cured polyurethanes from camelina oil polyols (expressed via glass transition temperature) were evaluated using differential scanning calorimetry and found to significantly exceed those made using castor oil. Overall, this study demonstrates that polyols from camelina oil can be produced with a range of viscosities and hydroxyl functionalities and are suitable to replace castor oil in polyurethane applications. The ability to adjust these parameters offers a significant advantage over castor oil.
Volume 107, 15 November 2017, Pages 378–385