High-Field1H-NMR Study of Poly(Vinyl Chloride) Defects
作者:
M.F. Darricades-llauro,
A. Michel,
A. Guyot,
H. Waton,
R. Petiaud,
Q.T. Pham,
期刊:
Journal of Macromolecular Science: Part A - Chemistry
(Taylor Available online 1986)
卷期:
Volume 23,
issue 2
页码: 221-269
ISSN:0022-233X
年代: 1986
DOI:10.1080/00222338608063389
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Radical poly(vinyl chlorides), (PVC), obtained in bulk and in suspension polymerizations, and their low molecular weight extracts have been thoroughly studied by high-field NMR to obtain better qualitative and quantitative analyses of their structural defects. Assignments have been achieved by1H-1H decoupling experiments and hyperfine spectral structure analysis of model compounds and low molecular weight extracts. Strong effects of the nature of the solvents used in1H-NMR analysis were observed. Most of the defects of these radical PVC's have been quantitatively estimated in terms of average number values in correlation with their [Mbar]n. End-groups of type [I'] (= −CH2−CH˭CH‒CH2C1) are about 0.5 per chain; internal double bonds can only be estimated by difference, and their amount increases with increasing conversion. A very low quantity of vinyl chain end [I'] (˭ ‒CHC1‒CH˭CH2) has been found only in low molecular weight extracts. For the three probable saturated chloromethyl ends [II] (˭‒CHCl‒CH2Cl), [III] (˭ ‒CH2‒CH2Cl), and [IV] (˭ >CH‒CH2C1), only [II] and [III] were definitely identified. Finally, in taking into account all the endgroups, it has been concluded that branches would be grafted throughout the process. On the average, 4 to 5 branches have been found per chain of high molecular weight PVC.
点击下载:
PDF (1427KB)
返 回