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Anionic Polymerization of Divinylbenzenes Possessing Methoxy Group
Author(s) -
Otake Kohei,
Matsumoto Masayoshi,
Tanaka Shunsuke,
Uchida Satoshi,
Goseki Raita,
Hirao Akira,
Ishizone Takashi
Publication year - 2017
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/macp.201600550
Subject(s) - anionic addition polymerization , divinylbenzene , polymer chemistry , chemistry , polymerization , copolymer , tetrahydrofuran , steric effects , polymer , organic chemistry , styrene , solvent
The anionic polymerizations of novel methoxy‐substituted divinylbenzenes possessing nonequivalent vinyl groups, such as 2‐methoxy‐1,4‐divinylbenzene ( 1 ), 4‐methoxy‐1,2‐divinylbenzene ( 2 ), and 4‐methoxy‐1,3‐divinylbenzene ( 3 ), are carried out with oligo(α‐methylstyryl)lithium (αMSLi) in the presence of potassium tert ‐butoxide ( t BuOK) in tetrahydrofuran at −78 °C. The poly( 1 )–poly( 3 ) obtained with αMSLi/ t BuOK are completely soluble and possess predicted molecular weights and narrow molecular weight distributions (MWD) ( M w / M n < 1.1). On the other hand, the corresponding symmetrical divinylbenzenes, 2‐methoxy‐1,3‐divinylbenzene ( 4 ) and 5‐methoxy‐1,3‐divinylbenzene ( 5 ), undergo anionic polymerization to afford polymers with broad MWDs, indicating the occurrence of a serious intermolecular side reaction. The stability of the propagating carbanion derived from 1–3 is demonstrated by the quantitative efficiency of the sequential copolymerization with tert ‐butyl methacrylate. The chemical structure of the repeating unit of poly( 1 )–poly( 3 ) is characterized by the 1 H and 13 C nuclear magnetic resonance measurements, suggesting that the polymerization of asymmetrical divinylbenzenes, 1 – 3 , proceeds mainly on one of the nonequivalent vinyl groups. The electronic and steric effects of the electron‐donating methoxy group play important roles in realizing the living anionic polymerization of these divinylbenzenes. The resulting poly( 1 )–poly( 3 ) show a thermal cross‐linking property over 300 °C, indicating the reactivity of the residual pendant vinyl group in each repeating unit.