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Efficient Synthesis and Copolymerization of Poly(acrylic acid) and Poly(acrylic ester) Macromonomers: Manipulation of Steric Factors
Author(s) -
McHale Ronan,
Aldabbagh Fawaz,
Carroll William M.,
Yamada Bunichiro
Publication year - 2005
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.200500269
Subject(s) - macromonomer , polymer chemistry , polymerization , copolymer , chemistry , acrylate , chain transfer , acrylic acid , butyl acrylate , radical polymerization , organic chemistry , polymer
Summary: Macromonomers have been prepared by polymerization of acrylic acid (AA) and tert ‐butyl acrylate ( t BA) in the presence of the addition‐fragmentation chain transfer (AFCT) agents, ethyl α ‐(bromomethyl)acrylate (EBMA) and tert ‐butyl α ‐(bromomethyl)acrylate (BBMA). Chain transfer constants of 1.25 (EBMA) and 1.14 (BBMA) in the AA polymerization, and 2.42 (EBMA) and 1.75 (BBMA) in the t BA polymerization were obtained. The reduction in molecular weight with increasing concentration of AFCT agent and efficient introduction of 2‐carbalkoxy‐2‐propenyl ω ‐end group was indicative of macromonomer formation. Polymerizations were retarded with increasing concentrations of AFCT agent and increases in the absolute concentration of EBMA slowed down the polymerization of AA but not t BA. The difference between EBMA and BBMA was less significant with t BA; more efficient macromonomer synthesis was indicated by less retardation and greater double bond retention at higher conversions. Copolymerizations of poly(AA) and poly( t BA) macromonomers with styrene indicated that the former was more reactive towards the St propagating radical. The results are rationalized in terms of the steric hindrance imposed by the tert ‐butyl group. Poly( t BA) macromonomer was successfully hydrolyzed to give an alternative route to the poly(AA) macromonomer.Reaction mechanism for macromonomer synthesis using AFCT.