ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Polymerization of styrene in toluene solution at 50°C was found not to be initiated with sufficiently pure tetrabenzylzirconium or -titanium. However, a cocatalytic effect of water was observed with a maximum rate for a mole ratio H2O/Mt (Mt = Zr or Ti) close to 0,1. No activities were observed for the hypothetical compounds (C6H5CH2)3Mt - O - Mt(CH2C6H5)3. This cocatalytic effect was also observed with tribenzylchlorozirconium (1), tribenzylzirconiooxytriphenylsilane (2), or 6,6-dibenzyl-2,2,4,4-tetramethyl-1,3,5-trioxa-2,4-disila-6-zirconacyclohexane (3). Styrene polymerizations were also initiated by supported catalysts obtained by reaction of Zr(CH2C6H5)4 with aluminium oxide or silicium oxide pre-dried at various temperatures. The activities of such systems were equal or slightly lower than those obtained with the system Zr(CH2C6H5)4/H2O (mole ratio 10 : 1). The resulting polystyrenes have very high molecular weights with very broad distribution. Copolymerization experiments with methyl methacrylate gave as main product a copolymer containing only 4% of monomeric units of styrene. A discussion of all results led to the conclusion that the main polymerization involves an anionic-type propagation.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1983.021840708
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