Journal of Polymer Science Part A: Polymer Chemistry, Vol.48, No.23, 5289-5297, 2010
One-Pot Enzymatic Route to Tetraallyl Ether Functional Oligoesters: Synthesis, UV Curing, and Characterization
An enzymatic one-pot route in bulk was used to synthesize tetraallyl ether (tAE) functional oligomers based on divinyl adipate, 1,4-butanediol and trimethylolpropane diallyl ether. By using lipase B from Candida antarctica as catalyst and varying the stoichiometric ratio of monomers, it was possible to reach targeted molecular weights (from 1300 to 3300 g mol(-1)) of allyl-ether functional polyesters. The enzyme catalyzed reaction reached completion (>98% conversion based on all monomers) within 24 h at 60 degrees C, under reduced pressure (72 mbar) resulting in similar to 90% yield after filtration. The tAE-functional oligoesters were photopolymerized, without any purification other than removal of the enzyme by filtration, with thiol functional monomers (dithiol, tetrathiol) in a 1: 1 ratio thiol-ene reaction. The photo-initiator, 2,2-dimethoxy-2-phenylacetophenone, was used to improve the rate of reaction under UV light. High conversions (96-99% within detection limits) were found for all thiol-ene films as determined by FT-Raman spectroscopy. The tAE-functional oligoesters were characterized by NMR, MALDI, and SEC. The UV-cured homopolymerized films and the thiol-ene films properties were characterized utilizing DSC and DMTA. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5289-5297, 2010
Keywords:CaIB;enzymatic polycondensation;enzymes;films;networks;photopolymerization;polycondensation;polyesters;polyester films;thermoset;thiol-ene;UV curing