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Long‐chain and short‐chain branches in ethene‐methyl acrylate copolymers studied by quantitative 13 C NMR spectroscopy
Author(s) -
Boxtel Marc H. C. M. van,
Busch Markus,
Lehmann Stephan
Publication year - 2000
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/(sici)1521-3935(20000201)201:3<313::aid-macp313>3.0.co;2-x
Subject(s) - copolymer , polymer chemistry , acrylate , methyl acrylate , intramolecular force , chain (unit) , materials science , bar (unit) , low density polyethylene , alkylation , spectroscopy , chemistry , polyethylene , organic chemistry , polymer , catalysis , physics , quantum mechanics , astronomy , meteorology
The frequency of long‐chain branches (LCBs) in ethene (E)‐methyl acrylate (MA) copolymers is investigated for material that was synthesized at 150°C and 2 000 bar at different levels of conversion but constant copolymer composition. The copolymers exhibit significantly more LCBs than found in LDPE synthesized under similar conditions. Moreover, it is found that the LCB frequency increases with conversion. At 0.3 mol‐% conversion 0.3 LCBs and at 4.0 mol‐% conversion 1.1 LCBs per 1 000 C atoms are observed. In addition, the frequency of short‐chain branches (SCBs) in the copolymers is investigated. About 9 mol‐% of the acrylate units are alkylated, which corresponds to numbers given in literature. As sensors, both LCB and SCB indices provide valuable information for simulation calculations to determine rate coefficients for inter‐ and intramolecular transfer reactions.