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Free‐radical polymerization of methyl methacrylate initiated by thiol alone
Author(s) -
Xia P.,
Cheng H.,
Yan D.
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070450403
Subject(s) - polymerization , monomer , thiol , polymer chemistry , methyl methacrylate , radical polymerization , chemistry , activation energy , photochemistry , polymer , organic chemistry
Three different alkyl thiols, i.e., n ‐propylthiol, isopropylthiol, and 2‐methyl‐2‐undecanethio1, were proved efficient to initiate the polymerization of methyl methacrylate at 40°C. The initial polymerization rate, R p , increases with increasing thiol concentration but cannot be described by a single‐power law. However, R p is proportional to 1.3th power of the monomer concentration, indicating the participation of monomer in the initiation reaction. With increase of the polarity of solvents, R p decreases, demonstrating the polar property of the initiating intermediate. The apparent activation energy of overall polymerization was calculated to be 9.3 kcal/mol. Molecular weight measurements indicated the twofold function of the thiol as both an initiator and a regulator.