ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A microstructure analysis of polychloroprenes by 1H and 13C NMR produced slightly different results which, however, are in good agreement. The main uncertainty concerned the assignment of the 1,4-cis and trans head-to-head and tail-to-tail additions. In the (+ 12, +70°C) region of polymerization temperatures the principal addition mode was 1,4. An increase in the polymerization temperature to 70°C increased the abnormal head-to-head, tail-to-tail additions, and 1,4-cis additions (6-7%), and all vinyl structures that were not higher than 2-3% were equally distributed between 1,2 and 3,4. Under the experimental conditions used in this study no isomerized vinyl structures were found. As in all radical polymerizations the influence of temperature on the propagation mechanisms, namely, the addition modes, was relatively weak, but because of the great number of possible addition modes in microstructure - physicomechanical relationships variations in the microstructure must be taken into account. Only 1H and 13C NMR are capable of determining these variations quantitatively.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1985.170230508
