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Syndiospecific Living Block Copolymerization of Styrenic Monomers Containing Functional Groups, and Preparation of Syndiotactic Poly{(4‐hydroxystyrene)‐ block ‐[(4‐methylstyrene)‐ co ‐(4‐hydroxystyrene)]}
Author(s) -
Kawabe Masanao,
Murata Masahide
Publication year - 2002
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 - 10.1002/1521-3935(20020101)203:1<24::aid-macp24>3.0.co;2-5
Subject(s) - copolymer , polymer chemistry , monomer , styrene , polymerization , chemistry , polymer , organic chemistry
At –25°C, the sequential block copolymerizations of 4‐( tert ‐butyldimethylsilyloxy)styrene (TBDMSS) and 4‐methylstyrene (4MS) were investigated by using a syndiospecific living polymerization catalyst system composed of (trimethyl)pentamethylcyclopentadienyltitanium (Cp*TiMe 3 ), trioctylaluminum (AlOct 3 ) and tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 ). The number‐average molecular weight ( M̄ n ) of the poly(TBDMSS)s increased linearly with increasing the polymer yield up to almost 100 wt.‐% consumption of TBDMSS used as 1 st monomer. The M̄ n value of the polymer after the second monomer (4MS) addition continued to increase proportionally to the polymer yield. The molecular weight distributions (MWDs) of the polymers remained constant at around 1.05–1.18 over the entire course of block copolymerization. It was concluded that the block copolymerizations of TBDMSS and 4MS with the Cp*TiMe 3 /B(C 6 F 5 ) 3 /AlOct 3 catalytic system proceeded with a high block efficiency. The 13 C NMR analysis clarified that the block copolymers obtained in this work had highly syndiotactic structure. By the deprotection reaction of silyl group with conc. hydrochloric acid (HCl), syndiotactic poly{(4‐hydroxystyrene)‐ block ‐[(4‐methylstyrene)‐ co ‐(4‐hydroxystyrene)]} (poly[HOST‐ b ‐(4MS‐ co ‐HOST)]) was successfully prepared.