Fish Oil Thermosetting Polymers: Synthesis, Structure, Properties and Their Relationships

Li, F., D. W. Marks, R. C. Larock, and J. U. Otaigbe

Department of Materials Science and Engineering

Iowa State University,

Ames, IA, USA.

Abstract

The cationic copolymn. of native or conjugated fish oil (FO or CFO) with divinylbenzene (DVB), norbornadiene (NBD) or dicyclopentadiene (DCP) comonomers initiated by boron trifluoride di-Et etherate (BF3 × OEt2) was conducted in an effort to develop useful biodegradable polymers with rationally designed structures from natural renewable resources. Polymers ranging from rubbers to hard plastics have been obtained. 1H NMR, 13C NMR, solid state 13C NMR, differential scanning calorimetry (DSC), and dynamic mech. anal. (DMA) have been used to characterize the structures and phys. properties of the fish oil polymers. The results indicate that the products are typical thermosetting polymers with densely crosslinked structures. These polymer materials have densities of approx. 1000 kg/m3, which appear to be independent of their compns. The structure of the bulk polymer is composed of 40-85 wt% of crosslinked polymer networks plasticized by 15-60 wt% of unreacted free oil. The moduli of the FO (.apprx.0.8 GPa) and CFO (.apprx.1.1 GPa) polymers at room temp. are found to be comparable to those of conventional petroleum-based plastics. The glass transition temps. of the polymers range from 50 to 150 ° C with a broad transition region. Thermogravimetric anal. (TGA) indicates three distinct decompn. temp. regions, i.e. 200-400 ° C, 400-560 ° C, and 560-800 ° C, which correspond to evapn. of the unreacted free oil, carbonization of the crosslinked polymer network, and oxidn. of the carbon, resp. The thermal stability of these materials is found to be largely dependent on the amt. of unreacted free oil mols. present in the bulk polymers. The CFO polymers have higher moduli and thermal stability than the FO polymers due to the lower amt. of free oil present in the CFO bulk polymers.