Anionic Polymerization of Divinylbenzenes Possessing Methoxy Group

作者：Otake Kohei; Matsumoto Masayoshi; Tanaka Shunsuke; Uchida Satoshi; Goseki Raita; Hirao Akira; Ishizone Takashi^*

来源：Macromolecular Chemistry and Physics, 2017, 218(12): 1600550.

DOI：10.1002/macp.201600550

• anionic polymerization
• cross-linking
• divinylbenzene derivatives
• living polymerization
• methoxy group

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(amethylstyryl) -lithium (aMSLi) in the presence of potassium tert-butoxide (tBuOK) in tetrahydrofuran at -78 degrees C. The poly(1)-poly(3) obtained with aMSLi/tBuOK are completely soluble and possess predicted molecular weights and narrow molecular weight distributions (MWD) (Mw/Mn < 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 1H and 13C 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 electrondonating 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 degrees C, indicating the reactivity of the residual pendant vinyl group in each repeating unit.

• 出版日期2017-6