首页   按字顺浏览 期刊浏览 卷期浏览 High-Field1H-NMR Study of Poly(Vinyl Chloride) Defects
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