ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Description / Table of Contents:
Comparative calculations are conducted for triad models of polyacrylonitrile (PAN) and poly(vinyl chloride) (PVC) using the semiempirical MNDO method. By comparing the so obtained geometrical, thermodynamical, and electronic values it is possible to obtain information concerning the variation in the properties of PAN with stereochemically different structures. Consequently, the glass transition temperature of syndiotactic PAN is predicted to be higher than that of the isotactic form. As in case of PVC, it is expected that decreasing the polymerization temperature would lead to the preferred formation of syndiotactic segments in PAN. The necessary temperature is, however, in the latter case much lower. The calculated acidities indicate that a higher tendency toward racemization is to be expected for syndiotactic PAN as compared with isotactic PAN.
Notes:
Zusammenfassend läßt sich sagen, daß sich die Modelle für die Diastereomere des PAN in ihren Stabilitäten und Reaktivitäten noch weniger unterscheiden als die entsprechenden PVC-Modelle. Daraus läßt sich der Schluß ziehen, daß eine Beeinflussung der Stereoregularität des PAN allein durch Erniedrigung der Polymerisationstemperatur nicht zu erreichen ist.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1989.021901123
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