ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The cationic polymerizations of dimethyl-1,3-butadienes with various catalysts in methylene chloride and toluene have been investigated. The activity of catalysts decreased in the order WCl6 〉 AcClO4 〉 SnCl4·TCA 〉 BF3OEt2. The homopolymerization rate of dimethyl-1,3-butadienes with WCl6, AcClO4, and SnCl4·TCA decreased in the order 1,3-dimethyl-1,3-butadiene 〉 2,3-dimethyl-1,3-butadiene 〉 1,2-dimethyl-1,3-butadiene 〉 2,4-hexadiene. The polymers prepared with WCl6, SnCl4.TCA, and BF3OEt2 were rubberlike polymers or white powders, whereas those prepared with AcClO4 were oily oligomers. The 1,4-propagation increased in the order 1,2-dimethyl-1,3-butadiene 〈 1,3-dimethyl-1,3-butadiene 〈 2,3-dimethyl-1,3-butadiene 〈 2,4-hexadiene. This order may indicate that the steric effect of methyl group determine primarily the microstructure of the polymer. The relative reactivity of dimethyl-1,3-butadienes toward a styryl cation decreased in the order 1,3-dimethyl-1,3-butadiene 〉 1,2-dimethyl-1,3-butadiene 〉 2,3-dimethyl-1,3-butadiene 〉 2,4-hexadiene. This order may be explained in terms of the stability of the resulting allylic cation.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1978.170160626
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