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Synthetic and mechanistic aspects of anionic polymerization of methyl methacrylate using tetrabutyl ammonium thioimidate
Author(s) -
Ge Fang,
Zhang Qun,
Wang Xiaowu
Publication year - 2021
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20200824
Subject(s) - polymerization , counterion , polymer chemistry , methyl methacrylate , chemistry , monomer , anionic addition polymerization , living anionic polymerization , polymer , molar mass distribution , ionic bonding , cationic polymerization , ionic polymerization , bulk polymerization , radical polymerization , organic chemistry , ion
The tetrabutylammonium salts of ionic organo‐initiator containing N,N' ‐diisopropylthiourea (TUA‐1) or N,N' ‐diethylthiourea (TUA‐2) serve as inexpensive initiators for the anionic polymerization of methyl methacrylate (MMA) at room temperature. The molecular weights of obtained polymers are in the range of 1500–22,700 g mol −1 and the molecular weight distributions are fairly broad ( Đ = 1.9–2.5) in optimized cases. The molar ratio of monomer to initiator can be achieved up to 800. Side‐reactions, for example, backbiting, transfer reactions result in the polymerization being a non‐living manner, thus leading to broad molecular weight distributions of the resulting polymers. The effects of counterion nature were also studied from the polymerization of MMA using TUA‐1 anion with sodium or potassium salts as counterions under identical conditions. Detailed investigation indicates that the polymerization proceeds via a sulfur anion initiated repeated 1,4‐Machael addition. In general, thioimidate initiators induced MMA polymerization feature certain induction periods, which is ascribed to slow addition thioimidate to CC double bond of MMA as a result of low initiator efficiency.