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High‐pressure free‐radical copolymerization of ethene and methyl acrylate
Author(s) -
Buback Michael,
Dröge Thomas
Publication year - 1997
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.1997.021981125
Subject(s) - copolymer , monomer , methyl acrylate , acrylate , reactivity (psychology) , polymer chemistry , chemistry , polymerization , bar (unit) , butyl acrylate , polymer , organic chemistry , medicine , alternative medicine , pathology , physics , meteorology
The free‐radical copolymerization of ethene (E) and methyl acrylate (MA) is studied between 220 and 290°C at 2000 bar. The reactions which have been induced thermally are carried out in a continuously operated device at total monomer conversions mostly below 1%. Monomer concentrations are obtained from measured mass fluxes. Copolymer composition is determined via elemental analysis. Reactivity ratio data, r E and r MA , are derived from non‐linear least squares fitting of the monomer mixture and copolymer compositions. r E and r MA , e.g., at 220°C and 2000 bar, are found to be 0,045 ± 0,002 and 5,3 ± 0,2, respectively. The r E and r MA values slightly, but significantly, differ from corresponding data for ethene‐butyl acrylate (BA) and ethene‐2‐ethylhexyl acrylate (EHA) copolymerizations. Toward higher temperature r E increases and the acrylate (MA, BA, EHA) reactivity ratio r A decreases. The temperature dependences of r E and r A can not be distinguished for the three ethene‐acrylate systems. From an experiment at two levels of polymerization pressure, 1500 and 2000 bar, the pressure dependence of r E has been estimated. The available data for r E and r A allow to model monomer concentration vs. polymer composition behavior of free‐radical ethene‐acrylate copolymerizations at technically relevant temperatures and pressures.