ISSN:
0887-624X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Thermal degradation of polychloroprene under nitrogen, especially at the initial stages, has been studied by using 1H-NMR, 13C-NMR and FT-IR spectroscopy. A model polymer of low molecular weight (Mn = 6300) was prepared to avoid gelation during degradation. None of isomerized 1,2 unit has been found in the original polymer. Allylic rearrangement of 1,2 unit was the first-stage reaction, which was finished within 30 min at 150°C. The extent of HCl loss was proportional to the decrease of isomerized 1,2 unit. It has been suggested that the next-stage reaction is dehydrochlorination of the isomerized 1,2 unit. The presence of terminal vinyl group and the increased amount of olefinic proton were not found in the degraded polymer. The back-biting mechanism involving a six-membered cyclization process is proposed for the dehydrochlorination. The thermal racemization has been also found to take place in the 3,4 unit.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1988.080260925
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