Styrene copolymerization using a metallocene-MAO initiator system. Homo- and copolymerization of styrene with some cycloalkenesReport as inadecuate




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The copolymerization of styrene with cyclohexene, 1-methyl-1-cyclohexene,and norbornene using ethenylbisindenylzirconium dichloride and methylaluminoxane,EtInd2ZrCl2-MAO, initiating systems has been tested. The resultsobtained with each styrene-cycloalkene couple, except styrene-norbornene, indicatea less effective polymerization process compared to styrene homopolymerization, inagreement with the electronic and steric effects present in each comonomer. Theelectronic I? effects of substituent groups, depending on their placement, largelyimprove the polymerization process, while bulky groups on or near the vinyl carbondouble bond of styrene decrease its effectiveness. The present study shows that thecopolymers obtained are amorphous and their composition showed a lower abundanceof comonomer units with respect to the initial feed. For comparison, theresults of the copolymerization of styrene-1-octadecene using the same initiatorsystem and polymerization process are included, a polymerization that indicates amore reactive process, and as the proportion of octadecene in the initial feedincreases, it showed a crystalline fusion temperature as well as a Tg in the styrene region which can be attributed to the formation of block styrene-octadecenecopolymers.Nota general

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Author: Rabagliati, Franco M.; - Yáñez, Daniela E.; - Canales, Daniel; - Quijada Abarca, Raúl; - Zapata, Paula A.; -

Source: http://repositorio.uchile.cl/



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