Synthesis of star polymer by means of the living polymerization of [(o-trifluoromethyl)phenyl]acetylene using a MoOCl4-based catalyst and the linking method

A star polymer was synthesized by addition of 1,4-diethynyl-2,5-dimethylbenzene as linking agent (30 °C, 24 h) after living polymerization of [(o-trifluoromethyl)phenyl]acetylene (o-CF3PA) with MoOCl4–n-Bu4Sn–EtOH catalyst (in anisole, 30 °C, 20 min; [Mo]=10 mM, [P∗]/[Mo]=40%, [o-CF3PA]0=200 mM). The Mn values of the living and star polymers were 8.1×103 and 5.3×104, respectively, according to gel permeation chromatography, while these values determined by multi-angle laser light scattering (MALLS) were 7.8×103 and 2.5×105. The Mw/Mn and arm number of the star polymer were 1.04 and 29, respectively, according to MALLS. The molecular weight and arm number of star polymer increased with increasing linking agent concentration and polymerization temperature.