(55c) Sustainable Polymeric Materials Prepared by Ultrafast Photo-Polymerization of Chemically Modified Vegetable Oils

Photopolymerization is a technique that uses light rather than heat to initiate polymerization reactions.  Photopolymerization has been used extensively in adhesives, coatings, and lithographic industries due to the high curing rates and spatial and temporal control realizable with it.  While conventional petroleum-based monomer feeds have been used in a highly energy efficient manner through photopolymerization, the development of polymeric materials based on renewable resources is critical to sustainability efforts.  In this work, vegetable oils were used as base materials for the fabrication of polymeric films by several photo-induced polymerization mechanisms.  Using real-time Raman spectroscopy, raw vegetable oils were shown not to undergo rapid photopolymerization at room temperature.  Thus, vegetable oils were chemically modified in order to increase reactivity by the addition of epoxide, (meth)acrylate, and norbornene moieties to the triglyceride molecules.  Modified oils were then polymerizable by radical, anionic, or cationic mechanisms depending on the functional groups attached to the oil substrate. The modified oils were photo-polymerized at room temperature, and quantitative conversions were achieved.  The physical/mechanical properties of the materials produced varied widely depending on the functional groups attached to the triglyceride and the polymerization mechanism used.  The glass transition temperature of polymer products was easily modified in both the breadth of the transition and the temperature at which the transition occurs by the blending of various modified oils with conventional monomers. Additionally, the cured materials were subjected to accelerated aging by high-temperature storage, simulated sunlight, and combinations of both.  The property development and stability of mechanical performance were correlated to the additives used to cure the materials.