Studies on Polyvinyl Chloride (Ii). Branching

Cotman, John D.

doi:10.1111/j.1749-6632.1953.tb36414.x

Cited by 73 publications

(2 citation statements)

References 21 publications

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“…These results basically agree with previously reported values. 9 The resonace of the quarternary carbon at the branch point cannot as yet be distinguished from the noise. It is necessary to carry out accumulation more than 256 times in order to identify the quaternary carbon resonance, because of the lack of signal enhancement due to the nuclear Overhauser effect.…”

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confidence: 99%

13C–{1H} Nuclear Magnetic Resonance Spectroscopy of Poly (vinyl chloride) and its Model Compounds

Inoue

Ando

Nishioka

1972

Polym J

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KEY WORDS13C-{1H} NMR / Poly(vinyl chloride) / Configuration / Tacticity / Branching / The 13 C-{1H) high-resolution NMR is of great interest in the study of higher order stereochemical placement of vinyl polymers 1 -4 , because carbon is the most essential atom constituting the skeletal bonds of the polymer chain.Recently Schaefer 5 showed the Fourier Transforms of the noise-decoupled, natural abundance 13 C-{1H) NMR of free induction decays of poly(vinyl chloride) (PVC), but the configurational assignments were not shown clearly.We measured 13 C-{ 1 H} NMR spectra of PVC and its dimer model compounds, i.e., mesa-and racemic-2,4-dichloropentanes. PVC was supplied by Prof. Benoit for the IUP AC Study Programm on Molecular Characterization of Commercial Polymers, and PVC-B was a commercial polymer with relatively high syndiotacticity produced by the Chatillon S.p.A. (Italy).13 C-{1H) spectra were observed by external locked field sweep in absorption mode at 25.14 MHz, using a JNM PS-100 spectrometer. Chemical shifts were represented in terms of parts per million using enriched 13 CH3OH as an external reference. The measurements of NMR were made using the neat liquid for the model compounds and the 20-%(w/v) solution of dimethylsulfoxide for PVC. The a-dichlorobenzene was also used as the solvent for PVC but no significant difference was observed.The NMR samples of PVC were first heated at about 150°C for several minutes to form a uniform solution and then settled at 70°C. At this temperature the solution formed a slightly loose gel and a change in color was not observed during a NMR measurement. Details of NMR measurement 246 are described in ref 3.13 C-{1H) spectrum of the mixture of dimer model compounds, wherein the molar ratio of mesa-isomer to racemic-isomer was approximately 1 : 3, is shown in Figure 1. The assignments of peaks are on the basis of their multiplet structures of weakely proton decoupled 13 C spectrum. All carbons of racemic-isomer appeared in a lower field compared to mesa-isomer. 13C -{1H} spectrum of 1 : 3 mixture of meso-and racemic-2,4-dichloropentane observed at 25.14 MHz, at room temperature.

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confidence: 99%

13C–{1H} Nuclear Magnetic Resonance Spectroscopy of Poly (vinyl chloride) and its Model Compounds

Inoue

Ando

Nishioka

1972

Polym J

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“…With the exception of direct NMR examination, the techniques used by the group to obtain information on short chain branching in PVC depend on prior conversion to a hydrocarbon by a reduction technique. Before 1977 (2), the technique was to replace the chlorine atoms by hydrogens using lithium aluminum hydride. Reduction with tributyl tin hydride, however, has proved safer and easier and so with the exception of one group, laboratory A, all the reductions reported here have been made using tin hydrides.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

Short chain branching in poly(vinyl chloride)

Park¹

1985

J. Vinyl Addit. Technol.

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The chemical modification of polymers for analytical purposes

Harwood

1968

Angew. Makromol. Chem.

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When it is possible to convert one polymer quantitatively into another, the derived polymer can sometimes be studied to obtain information about the original polymer. In other instances, the derived polymer can serve as a reference material for use in the development of polymer characterization procedures. This paper reviews the use of such techniques in studies on branching and stereoregularity in homopolymers and in studies on sequence distribution in copolymers. The reactions covered include hydrolysis, ammonolysis, alcoholysis, esterification, transesterification and the hydrogenation of polyhalocarbons and unsaturated polyhydrocarbons. In addition, recent studies on cyclization reactions in polymers are surveyed. Such studies can provide information about sequence distribution in copolymers. ZUSAMMENFASSUNG :Derivate von Polymeren, die durch quantitative Umwandlung entstanden sind, konnen in gewissen Fallen dazu benutzt werden, die Eigenschaften des Ausgangspolymeren zu untersuchen. Das Polymerderivat kann auch als Bezugssubstanz bei der Entwicklung von Methoden zur Charakterisierung von Polymeren dienen. I n dieser Arbeit wird uber die Anwendung derartiger Methoden fur Untersuchungen uber die Verzweigung und Stereoregularitiit von Homopolymeren und die Sequenzverteilung von Copolymeren berichtet. Es werden verschiedene Reaktionen beschrieben, darunter Hydrolyse, Ammonolyse, Alkoholpse, Veresterung, Umesterung und die Hydrierung von Polyhalogenkohlenwasserstoffen und ungesatt,igten Polykohlenwasserstoffen. Weiterhin wird ein uberblick uber neuere Ringschlufireaktionen an Polymeren gegeben. Derartige Reaktionen konnen fur Untersuchungen der Sequenzverteilung von Copolymeren von Wichtigkeit sein.

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Studies on Polyvinyl Chloride (Ii). Branching

Cited by 73 publications

References 21 publications

13C–{1H} Nuclear Magnetic Resonance Spectroscopy of Poly (vinyl chloride) and its Model Compounds

13C–{1H} Nuclear Magnetic Resonance Spectroscopy of Poly (vinyl chloride) and its Model Compounds

Short chain branching in poly(vinyl chloride)

The chemical modification of polymers for analytical purposes

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