Synthesis And Characterization Of Polyurethane From Plant Oil Fatty Acid

In order to protect the environment and to reduce our dependence on fossil fuels,a great deal of research effort has been and is still being devoted to the development of innovative technologies using renewable resources. Vegetable oils are abundant and cheap renewable resources which represent a major potential alternative source of chemicals suitable for developing safe environmentally products. The use of vegetable oils and natural fatty acids as starting raw materials offers numerous advantages: for example, inexpensive, abundant, low toxicity, and inherent biodegradability, thus they are considered to be one of the most important classes of renewable resources for the production of biobased polyurethanes materials. Comparing with polyurethanes derived from petrochemical polyols, the vegetable-oil-based polyols produce polyurethanes has been the subject of many studies. Moreover, due to the hydrophobic nature of triglycerides, vegetable oils produce PUs that have excellent chemical and physical properties such as enhanced hydrolytic, high tensile strength and elongation,high tear strength, and thermal stability.The biobased aromatic triols were designed and synthesized from oleic acid,10-undecenoic and erucic acid using optimized chemical reactions and purifications.These aromatic triols were synthesized by two different methods: cyclotrimerization of stearoyl alcohol, 10-undecyn-1-ol, and behenolic ester to obtain the aromatic triols or aromatic derivatives, and subsequent reduction of carboxylate groups to give primary hydroxyl groups. Analyses of these biobased aromatic triols were performed by nuclear magnetic resonance(NMR) and fourier transform infrared(FTIR). A series of biobased segmented polyurethanes based on these aromatic triols, 1,4-butanediol as a chain extender and 4,4`-methylenebis(phenyl isocyanate) as a coupling agent, were synthesized. Samples were prepared with hard-segment contents up to 50%. The morphologies and thermal stability of these polyurethanes were studied by FTIR spectroscopy, wide-angle X-ray diffraction(WAXD), differential scanning calorimetry(DSC), and thermogravimetry-differential thermal analysis(TG-DTA).The objective of this work was to study the effect of the biobased aromatic triols onthe morphology of the resulting crosslinked polyurethanes and to correlate the morphology with the properties of these biobased crosslinked polyurethanes. These results show that it is possible to exploit renewable resources to manufacture original and useful materials.