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Anionic polymerization of monomers containing functional groups, 11. Anionic polymerizations of alkynyl methacrylates
Author(s) -
Ishizone Takashi,
Uehara Gouki,
Hirao Akira,
Nakahama Seiichi,
Tsuda Katsuyuki
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980901)199:9<1827::aid-macp1827>3.0.co;2-z
Subject(s) - polymer chemistry , chemistry , polymerization , monomer , trimethylsilyl , anionic addition polymerization , living anionic polymerization , methyl methacrylate , tetrahydrofuran , methacrylate , cationic polymerization , molar mass distribution , solution polymerization , solvent , organic chemistry , polymer
Anionic polymerization of 2‐propynyl methacrylate ( 1 ), 3‐trimethylsilyl‐2‐propynyl methacrylate ( 2 ), 2‐butynyl methacrylate ( 3 ), and 3‐pentynyl methacrylate ( 4 ) was carried out in tetrahydrofuran at −78°C for 1 h. The employed initiator systems were (diphenylmethyl)potassium/diethylzinc (Et 2 Zn) and 1,1‐bis(4′‐trimethylsilyphenyl)‐3‐methylpentyllithium/lithium chloride (LiCl). Although poly( 1 ) was obtained quantitatively with each initiator system, the observed molecular weights were always higher than the predicted values and the molecular weight distributions were rather broad ( M̄ w / M̄ n > 1.3), indicating a side reaction at the acidic acetylenic proton. On the other hand, the polymerization of 2–4 , i.e., methacrylate monomers having no terminal acetylenic protons in the ester moieties, proceeded quantitatively under similar conditions. The resulting poly( 2–4 )s were found to possess the predicted molecular weights and narrow molecular weight distributions ( M̄ w / M̄ n < 1.1), indicating the living character of the polymerization systems. The trimethylsilyl protecting group of poly( 2 ) was completely removed to form a poly( 1 ) having well‐defined chain structures by treating it with potassium carbonate in a mixed solvent of THF and methanol at room temperature for 1 h.