Physico-Chemical Characterization of Poly(vinyl Chloride). IV. Branching
作者:
M.D. Baijal,
T.S. Wang,
R.M. Diller,
期刊:
Journal of Macromolecular Science: Part A - Chemistry
(Taylor Available online 1970)
卷期:
Volume 4,
issue 4
页码: 965-977
ISSN:0022-233X
年代: 1970
DOI:10.1080/00222337008060991
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Degree of branching in PVC as a function of its temperature of polymerization has been determined by the catalytic hydrogenation (LiAlH4) of the polymer followed by IR measurements. The samples used were prepared at 55, 90, 130, and 160°C. A branching calibration curve (ACH3/ACH2vs CH3/CH2) was established for linear hydrocarbons, and was found to follow the relation, ACH3/ACH2= 20(CH3/CH2). This equation was used to characterize the branching indices of PVC samples studied. Branching values in units of 100(CH3/CH2) were as follows: 55°C (1.92), 90°C (1.95), 130°C (2.61), and 160°C (2.96). These results are in agreement with the theoretical prediction that the degree of branching in PVC should decrease with the lowering of its temperature of polymerization because the energy of activation for the propagation step is smaller than that for chain the transfer step.
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