Polymerization of 1-(1-Naphthyl)-1-propyne by Nb and Ta Catalysts and Polymer Properties: Effects of the 1-Naphthyl Group

Abstract 1-(1-Naphthyl)-1-propyne polymerized in the presence of NbCl5–cocatalyst systems to give virtually selectively a new polymer ca. 3 × 105) in high yields. Catalysts based on TaCl5 produced mixtures of the polymer and cyclotrimers. The polymer was a pale-yellow solid soluble in various organic solvents (e.g., toluene, CHCl3), and formed a free-standing film on solution casting. The onset temperature of the weight loss of the polymer in air was ca. 340 °C, which is higher than that (280 °C) of poly(1-phenyl-1-propyne) [poly(1-PP)]. The oxygen permeability coefficient at 25 °C was 80 barrers and one order of magnitude higher than that of poly(1-PP). These results are explicable in terms of the steric effects of the 1-naphthyl group.