1963 Volume 20 Issue 219 Pages 422-429
The polymerization of a-methylstyrene initiated by Al Et, Cl3-n, (n=1, 2)-Ti CI4 systems or Al R3-Ti Cl4 systems of different size R (alkyl group) at -78°C was studied. For Al Etn Cl3, Al Et C12 and Al Et2C1, and for Ai R3, Al Et3, Al (i-Bu) 3 and Al (Hex) 3 were used respectively. The conversion and the degree of polymerization (DP) at a definit time are influenced distinctly by the kinds of alkylaluminums and by the aging conditions of the catalyst systems. The order of catalyst activity defined by the DP of the polymers are as follows:
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The corresponding DP varied within the range from 500 to 3000 for the first series and from 800 to 5000 for the second series respectively. It is speculated that the cause of the above mentioned phenomena due to the different counter anions of active species. The structure of the active species are discussed on the basis of the reaction process of A1R3 or A1Eta Cl3-n with Ti Cl4.
