Two‐dimensional NMR characterization of propylene copolymers

Abstract

Newly developed two‐dimensional NMR techniques are used to characterize homopolypropylene and copolymers of propylene with ethylene and butylene. Both homonuclear and heteronuclear shift‐correlated experiments have been attempted. The most useful technique for the copolymers is 13C‐1H shift correlation, whereby the one‐dimensional 1H‐NMR spectra of these copolymers are completely interpreted for the first time. Although the 1H resonances are heavily overlapped, the use of a computerized “analytical” approach permits pertinent information to be obtained from the one‐dimensional 1H‐NMR spectra.

Ethylene Polymerization by Palladium Alkyl Complexes Containing Bis(aryl)phosphino-toluenesulfonate Ligands

“…However, the 13 C NMR spectra of low molecular weight polyethylenes generated at high polymerization temperature (entries 2, 9) and/or in the presence of acetonitrile (entry 3) show that the internal olefins are mainly 2-olefins (90%), with only small amounts of 3-olefins (10%), and that the E / Z ratio is ca. 3:1 (Figure ). – The polyethylenes obtained with 2a , 6a , and 6b have number average molecular weights ( M n ʼs) between 6000 and 19 000 and polydispersities in the range of 2.0 to 2.9, as determined by GPC. The M n values determined by 1 H NMR assuming that there is one CC unit per chain are similar to those obtained by GPC.…”

Pesticides

“…This procedure simulated homopolymer and copolymer spectra of increasing complexity for various structural types and provided good results. Characterization of EPM was achieved with a two-dimensional NMR technique (16) which utilized 13C-'H shift correlation. This allowed a complete computer interpretation of the one-dimensional 'H NMR spectra even when the resonances are heavily overlapped.…”

Microstructure analysis of methyl acrylate/methyl methacrylate copolymers by two‐dimensional NMR spectroscopy

“…[3][4][5][6][7][8][9][10][11][12][13][14] Homo-and copolymers of acrylates and methacrylates exhibit large number of physical properties, which make them important from commercial viewpoint, inducing many groups to study their microstructure. [15][16][17][18][19][20][21][22][23][24][25][26][27][28] Kim and Harwood have reported the sequence distribution of ␣-methyl, methane, and methylene carbon resonances in methyl acrylate/ methyl methacrylate copolymers by 13 C{ 1 H} NMR spectroscopy.…”