ISSN:
0360-6376
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The polymerization of butadiene by lithium-based initiators in aliphatic hydrocarbon solvents in the presence of dipiperidinoethane gives a highly 1,2 structure. This system was studied to determine the factors that govern the structure. The effect of this complexing agent on the kinetics of propagation, the microstructure of the polymer, and the ultraviolet spectrum of the active chain end was measured. The results suggest that more than one solvated species form, all giving highly 1,2 polymer structures, but that a solvate containing one chain end with one dipiperidinoethane molecule is the principal reacting species which gives close to 100% 1,2 structure. This reacting center has a high proportion of trans-structure in the allyllic ion, únlike most complexed active chain ends, which are often highly cis. It is this transstructure in the ion that is thought to be responsible for the polymer structure.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1985.170230714
