ISSN:
0022-3832
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
A study of the infrared absorption spectra of polychloroprenes made at temperatures ranging from -40 to 100°C. has made possible identification and estimation of the major structural features of these polymers. It is confirmed that 1,4 polymerization of chloroprene accounts for the greatest part of the structure of all neoprenes, ranging from 99% in -40°C. polymers to ca. 84% in 100°C. polychloroprenes. Of this 1,4 polymer only a small fraction has the cis configuration. This proportion increases from less than 5% in -40°C. polymer to ca. 13% in 100°C. polymer. Small amounts of branched structures that result from 1,2 and 3,4 polymerization are observed. These also increase in concentration with higher polymerization temperatures but do not account for more than 2.5% each even in 100°C. polychloroprenes. The portion of these polymers unaccounted for by these observations amounts at the most to 10% in 100°C. polymers. It is suggested that this part of the structure is that formed by hydrolysis and/or rearrangement of a part of the tertiary allylic chloride units which result from 1,2 polymerization of chloroprene. It is shown that only 50% of an acid-catalyzed ionic polychloroprene can be accounted for by structures recognized in free-radical polychloroprenes.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1954.120136905
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