METATHESIS COPOLYMERIZATION OF NORBORNENE WITH TERT-BUTYLACETYLENE INITIATED BY A TUNGSTEN CARBENE COMPLEX

Metathesis copolymerization of norbornene (NBE) with tert-butylacetyle ne (t-BA) at a feed ratio of 1:1 initiated by a tungsten carbene compl ex was investigated under various conditions. Results obtained from ti me-conversion curves indicated that the reactivity of tert-butylacetyl ene was several times greater than that of norbornene. The copolymer w as obtained in a higher yield and a larger molar mass in the solvent C Cl4 than those of other chlorinated hydrocarbons such as CHCl3 and CH2 Cl2. A larger molar mass and higher yield of copolymer wen: also obtai ned in the presence of a Lewis acid such as AlCl3. The activity of the tungsten carbene complex was obviously affected by Lewis acidity. C-1 3 NMR analysis results revealed a content of t-BA unit of the copolyme r in the presence of a Lewis acid. When copolymerization of norbornene (M(1)) with tert-butylacetylene (M(2)) in toluene was studied at 30 d egrees C, the monomer reactivity ratios were calculated to be r(1) = 0 .42 (+/- 0.02) and r(2) = 2.20 (+/- 0.05) with the method used by Mayo and Lewis. When in chlorinated solvents the copolymer was irradiated with ultraviolet light, the copolymer degraded and the rate of degrada tion was found to be the greatest in highly chlorinated solvents such as CCl4. Thermogravimetric analysis results of the copolymer indicated that there was no significant loss of mass that occurred below 250 de grees C under nitrogen.