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Conventional and RAFT radical copolymerizations of β‐pinene with N ‐substituted maleimides
Author(s) -
Wang Yi,
Chen Qing,
Liang Hui,
Lu Jiang
Publication year - 2007
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2294
Subject(s) - copolymer , raft , chemistry , pinene , polymer chemistry , chain transfer , maleimide , monomer , solvent , reactivity (psychology) , organic chemistry , radical polymerization , polymer , medicine , alternative medicine , pathology
Abstract The feasibility of the radical copolymerizations of β‐pinene with three N ‐substituted maleimides, i.e. N ‐phenylmaleimide (PhMI), N ‐methylmaleimide (MeMI), and N ‐ethylmaleimide (EtMI), was clarified for the first time. The copolymerization rates decreased in the order PhMI > MeMI > EtMI. A marked penultimate effect on the activity of the N ‐substituted maleimide‐terminated radicals was found in these copolymerizations. The penultimate monomer reactivity ratios evaluated by the nonlinear method were r 1 = 0.10, r ′ 1 = 8.30, r 2 = r ′ 2 = 0 for PhMI–β‐pinene, r 1 = 0.20, r ′ 1 = 7.09, r 2 = r ′ 2 = 0 for MeMI–β‐pinene, and r 1 = 0.16, r ′ 1 = 6.50, r 2 = r ′ 2 = 0 for EtMI–β‐pinene. Furthermore, the possible controlled copolymerizations of β‐pinene and N ‐substituted maleimides were then attempted via the reversible addition‐fragmentation chain transfer (RAFT) technique. In the presence of RAFT agent 1‐phenylethyl phenyldithioacetate, the copolymerization of β‐pinene with MeMI or EtMI was retarded severely. However, much smaller retardation was observed in the RAFT copolymerization of β‐pinene with PhMI, and, more importantly, the copolymerization exhibited typical features of a controlled system. The solvent effect on the RAFT copolymerization of β‐pinene and PhMI was also investigated using matrix‐assisted laser desorption ionization time‐of‐fight mass spectrometry (MALDI‐TOF‐MS) analysis. The results clearly indicated that copolymerization in tetrahydrofuran suffered from competitive transfer and termination side‐reactions arising from the solvent in spite of the presence of the RAFT agent. Copyright © 2007 Society of Chemical Industry