Room temperature living cationic polymerization of styrene with HX-styrenic monomer adduct/FeCl3 systems in the presence of tetrabutylammonium halide and tetraalkylphosphonium bromide salts
✍ Scribed by Sanjib Banerjee; Tapas K. Paira; Atanu Kotal; Tarun K. Mandal
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 663 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
Living cationic polymerization of styrene was achieved with a series of initiating systems consisting of a HX-styrenic monomer adduct (X ¼ Br, Cl) and ferric chloride (FeCl 3 ) in conjunction with added salts such as tetrabutylammonium halides
) and in toluene. Comparison of the molecular weight distributions (MWDs) of the polystyrenes prepared at different temperatures (e.g., À25 C, 0 C and 25 C) showed that the polymerization is better controlled at ambient temperature (25 C). The polymerization was almost instantaneous (completed within 1 min) and quantitative (yield w100%) in CH 2 Cl 2 . In CH 2 Cl 2 , polystyrenes with moderately narrow (M w /M n w 1.33-1.40) and broad (M w /M n w 1.5-2.4) MWDs were obtained respectively with and without nBu 4 N þ Y À . However, in toluene, the MWDs of the polystyrenes obtained respectively with and without nBu 4 N þ Y À /nR 0 4 P þ Br À were moderately narrow (M w /M n ¼ 1.33-1.5) and extremely narrow (M w /M n ¼ 1.05-1.17). Livingness of this polymerization in CH 2 Cl 2 was confirmed via monomer-addition experiment as well as from the study of molecular weights of obtained polystyrenes prepared simply by varying monomer to initiator ratio. A possible mechanistic pathway for this polymerization was suggested based on the results of the 1 H NMR spectroscopic analysis of the model reactions as well as the end group analysis of the obtained polymer.