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|Title:||Metathesis copolymerization of norbornene with tert-butylacetylene initiated by a tungsten carbene complex|
|Citation:||Liaw, D.-J.,Chiang, H.-H.,Jin, B.-H.,Kang, E.N.-T. (1996). Metathesis copolymerization of norbornene with tert-butylacetylene initiated by a tungsten carbene complex. European Polymer Journal 32 (2) : 215-221. ScholarBank@NUS Repository.|
|Abstract:||Metathesis copolymerization of norbornene (NBE) with tert-butylacetylene (t-BA) at a feed ratio of 1:1 initiated by a tungsten carbene complex was investigated under various conditions. Results obtained from time-conversion curves indicated that the reactivity of tert-butylacetylene was several times greater than that of norbornene. The copolymer was obtained in a higher yield and a larger molar mass in the solvent CCl4 than those of other chlorinated hydrocarbons such as CHCl3 and CH2Cl2. A larger molar mass and higher yield of copolymer were also obtained in the presence of a Lewis acid such as AlCl3. The activity of the tungsten carbene complex was obviously affected by Lewis acidity. 13C NMR analysis results revealed a content of t-BA unit of the copolymer in the presence of a Lewis acid. When copolymerization of norbornene (M1) with tert-butylacetylene (M2) in toluene was studied at 30°C, the monomer reactivity ratios were calculated to be r1 = 0.42 (±0.02) and r2 = 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 degradation 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°C under nitrogen. Copyright © 1996 Elsevier Science Ltd All rights reserved.|
|Source Title:||European Polymer Journal|
|Appears in Collections:||Staff Publications|
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