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A route to quantitative 13 C NMR analysis of multicomponent polyesters
Author(s) -
Hvilsted Søren
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910520118
Subject(s) - polyester , adipate , adipic acid , isophthalic acid , chemistry , propane , ethylene glycol , carbon 13 nmr , materials science , polymer chemistry , organic chemistry , terephthalic acid
A protocol for quantitative sequential 13 C NMR analysis is developed for polyesters composed of trimethylol propane (TMP), neopentyl glycol (NPG), and adipic and isophthalic acids. TMP centred, structural models with methyl adipate and isophthalate branches in all possible combinations are synthesized and purified. A detailed 13 C NMR investigation of the models unequivocally allows the identification of the TMP polyester structural sequences through the quaternary TMP carbon multiplicity. Spin‐lattice relaxation times, T 1 , of model quaternary TMP carbons are in the 2.3–5.2 s range, depending on the size of the specific model. This relaxation behaviour defines the experimental conditions for obtaining the quantitative assessment of all polyester polyol structural sequences based on quaternary TMP and NPG carbons. The special case dealt with here additionally centers all acid moieties between poyols in triads and thus makes quantitative determinations of all polyester constituents possible.