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1 H and 13 C NMR of PMMA macromonomers and oligomers ‐ end groups and tacticity
Author(s) -
Mccord Elizabeth F.,
Anton Waifong L.,
Wilczek Lech,
Ittel Steven D.,
Nelson Lissa T. J.,
Raffell Keith D.,
Hansen Joan E.,
Berge Charles
Publication year - 1994
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19940860106
Subject(s) - macromonomer , tacticity , nmr spectra database , polymer chemistry , end group , tetramer , materials science , chemistry , spectral line , polymerization , polymer , organic chemistry , physics , astronomy , enzyme
1 H NMR and 13 C NMR have been used to study the end groups and tacticity in PMMA macromonomers and oligomers. These macromonomers are terminated almost exclusively in one vinylidene group per chain. The end group signals from the macromonomers are identified in both the 13 C and 1 H NMR spectra. The spectra of the purified oligomers (n = 1‐4) were used to aid in assignment. The macromonomers are predominantly syndiotactic, and the tacticity measured is consistent with Bernoullian statistics. The tetramer is a mixture of r and m isomers in a 4:1 ratio. It is shown that T 1 experiments can provide a useful method of distinguishing resonances due to low molecular weight impurities from those due to stereochemical or isomeric effects in macromonomers. The absence of internal double bonds was confirmed by isomerizing the vinylidene group of several oligomers and of the macromonomer, and verifying the absence of the isomerized signals in the NMR spectra of the original materials.