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Well‐defined graft copolymers containing a poly(methacrylate) backbone and functional or block poly(vinyl ether) side chains
Author(s) -
Zhang Hongmin,
Ruckenstein Eli
Publication year - 1999
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(19990801)200:8<1975::aid-macp1975>3.0.co;2-u
Subject(s) - copolymer , cationic polymerization , polymer chemistry , living cationic polymerization , vinyl ether , monomer , side chain , polymerization , chemistry , methacrylate , methyl methacrylate , chain transfer , materials science , polymer , radical polymerization , organic chemistry
The anionic random copolymerization of methyl methacrylate (MMA) and 2‐(1‐acetoxyethoxy)ethyl methacrylate (AEEMA) was carried out using 1,1‐diphenylhexyllithium (DPHL) as initiator, in the presence of LiCl ([LiCl]/[DPHL] 0 = 2), in tetrahydrofuran (THF), at –60°C. The resulting polymer, poly‐(MMA‐ co ‐AEEMA), has a controlled molecular weight and a narrow molecular weight distribution ( M w / M n = 1.05 ˜ 1.09). Without quenching, toluene, EtAlCl 2 and a functional monomer [2‐acetoxyethyl vinyl ether (AcVE), 2‐chloroethyl vinyl ether (ClVE) or 2‐vinyloxyethyl methacrylate (VEMA)] were introduced into the above THF solution of the copolymer at 20°C. Every side chain of AEEMA unit of poly(MMA‐ co ‐AEEMA) was activated by EtAlCl 2 to induce the cationic polymerization of the functional monomer. THF, which was used as solvent in the preparation of the copolymer of MMA and AEEMA, acted as a Lewis base in the latter cationic polymerization, thus stabilizing the propagating site. By using this procedure, a controlled cationic polymerization of a functional monomer was achieved and a well‐defined graft copolymer with functional side chains was obtained. Instead of a single functional monomer, the simultaneous addition of isobutyl vinyl ether (IBVE) and AcVE, ClVE or VEMA during the second step cationic polymerization process generated a graft copolymer with random copolymer side chains. Furthermore, a graft copolymer with block side chains could also be prepared by performing a block copolymerization during the second cationic grafting step by adding sequentially AcVE (ClVE or VEMA) and IBVE or vice versa. Every graft copolymer thus obtained possessed a high purity, controlled graft number and molecular weight as well as a narrow molecular weight distribution ( M w / M n = 1.12 ˜ 1.25).