(337b) Dual Photo and Thermally Polymerizable Monomers Derived From Methyl Esters of Vegetable Oils

Dual
Photo and Thermally Polymerizable Monomers Derived from Methyl Esters of Vegetable
Oils

Brian
Dillman and Julie L.P. Jessop

Photo-polymerization
or polymerization initiated by light is a facile material synthesis technique
used widely in coating, adhesive, lithographic, and dental restorative
applications. A wide variety of photo-polymerizable monomers are available that
result in a range of polymer properties. Of the monomers available, few are
derived from renewable resources. In this study, methyl esters of soybean and
linseed oil, produced using standard biodiesel synthetic procedures, were used
to synthesize hybrid monomers (i.e., monomers bearing two types of polymerizable
functional groups). The methyl esters were amidated with ethanol amine,
resulting in α-hydroxy amides of vegetable
oil. In one case, the double bonds in the fatty acid residues were epoxidized
using H₂O₂ and acetic acid. In another case, the double
bonds were not functionalized further. The terminal hydroxyl group was then
reacted with an isocyanate acrylate monomer, resulting in acrylated amides of
vegetable oil or acrylated epoxidized amides of vegetable oil. Both monomer
types were formulated with photo-initiators, and the rapid acrylate
photo-polymerization was observed by real-time vibrational spectroscopy. After
photopolymerization, the materials were annealed at higher temperatures to
promote cross-linking through the epoxide moieties or double bonds in the fatty
acid residues by ring-opening or alkyd-type reactions, respectively. The degree
of cross-linking for each monomer type was evaluated by measuring the
cross-link density of the polymer before and after annealing using dynamic
mechanical analysis. The materials developed in this study incorporate approximately
60 wt% renewable materials using green synthetic chemistry and low energy
demand processing methods. The high efficiency of monomer and polymer synthesis
was accomplished by minimizing solvent use, selecting reactions that proceed to
high yields, and utilizing photopolymerization. The polymers prepared have
unique properties which allow for simple processing of polymers to complex
shapes.