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Stereochemical analysis of acrylic copolymers with large polar side groups by NMR spectroscopy
Author(s) -
Román Julio San,
Gallardo Alberto
Publication year - 1996
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10509
Subject(s) - comonomer , copolymer , tacticity , polymer chemistry , materials science , reactivity (psychology) , monomer , polymerization , nuclear magnetic resonance spectroscopy , radical polymerization , methacrylamide , methacrylate , polymer , chemistry , organic chemistry , acrylamide , medicine , alternative medicine , pathology , composite material
NMR spectra give abundant information at the microstructural level. When pseudoasymmetric carbon atoms are present in the monomeric repeating units, it is possible to obtain valuable information about the relative stereochemical configuration of the side substituents of the pseudoasymmetric center. This is the best way to know the tacticity of a polymer and the cotacticity parameters of copolymers, as well as the average distribution of comonomeric units along the chains, according to the polymerization mechanism. In this work, we present the microstructural and stereochemical characterization of acrylic copolymers prepared by free radical copolymerization of 2‐hydroxyethyl methacrylate with a methacrylic ester or methacrylamide derivative, bearing polar side groups of biomedical interest. These copolymer systems were analyzed by 1 H‐NMR spectroscopy to determine the average molar composition, and the corresponding reactivity ratios, and by 13 C‐NMR to study the microstructural and stereochemical configuration of comonomer sequences in terms of triads and pentads. Analyses account for the mechanism of polymerization, which fits first order Markov statistics for the addition of comonomers to free radical growing ends. The stereochemical distribution is described by a Bernoullian trial.