Rapid Hyperbranched Polythioether Synthesis Through Thiol-Michael Addition Reaction

In this study, two types of hyperbranched (HB) polythioether could readily be achieved in a short time at ambient temperature through a thiol-Michael addition reaction. Dimethyl acetylenedicarboxylate (DMADC) or methyl propiolate (A(2)) and trimethylolpropane tris(3-mercaptopropionate) (B-3) monomers were reacted using an organobase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as a catalyst in chloroform at room temperature to provide subsequent HB polythioethers. The effect of TBD concentration on the polymerization was studied for the DMDAC case monitoring the molecular weight evolution against time. HB polythioethers were characterized using spectroscopic (nuclear magnetic resonance) and chromatographic (gel permeation chromatography with refractive index and light-scattering detectors) techniques. (c) 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 824-830