III International Conference

PP-II-89OLEFINS HOMO- AND COPOLYMERIZATION IN THE MEDIUM OF LIQUIDPROPYLENE WITH METALLOCENE CATALYTIC SYSTEMSNedorezova P.M., Kovalchuk A.A., Klyamkina A.N., Aladyshev A.M., Tsvetkova V.I.,Lemenovskii D.A. 1 , Shklyaryk B.F. 2N.N. Semenov Institute of Chemical Physics Russian Academy of Science, Moscow, Russia1 Department of Chemistry Lomonosov Moscow State University, Moscow, Russia2 Topchiev Institute of Petrochemical Synthesis Russian Academy of Science, Moscow, RussiaE-mail: pned@chph.ras.ruPropylene homo- and copolymerization with ethylene and higher α-olefins with higheffective metallocene catalysts with different type of symmetry were studied. Isotactic,syndiotactic, hemiisotactic and stereoblock PP were produced. Metallocene catalystsproduced copolymers propylene-ethylene with a tendency to alternating or randomcomonomer incorporation in the polymer chain. The distinct feature of propylenecopolymerization with higher α-olefins on isospecific metallocene catalytic systems inpropylene medium – the proximity of comonomer relative reactivity ratios (r 1 ~r 2 ~1) thatindicates ideal nature of copolymerization processes in studied conditions. Polypropylenemodification with insignificant comonomer content allows to change mechanical properties ofcopolymers dramatically.The highly effective homogeneous metallocene (MC) catalytic systems opened newopportunities for synthesis of different polymer materials with unique properties. Newcatalysts have allowed to control microstructure, molecular weight characteristics andsynthezing almost of all kinds of stereoregular polymers. Metallocene systems have a singleactive centers and allow to obtain copolymers with uniform distribution of comonomers.The number of MC differ in symmetry type (C 1 , C 2 and C S ), the nature of bridge andligands were studied in processes of propylene polymerization and propylene and α-olefins(C 2 -C 8 ) copolymerization in a medium of liquid propylene. Homo- and copolymerization inbulk of propylene allows obtaining metallocene polymers with ultimately high yields and highmolecular weights.Polymerization was carried at 30-80 о С with the use of different cocatalysts -polymethylalumoxane (MAO) or with partial replace of MAO by (iso-C 4 H 9 ) 3 Al. Theinfluence of the metallocene structures, the polymerization temperature, the comonomernature on the activity, molecular weight characteristics, stereoregularity, thermophysical andmechanical properties of polymers will be regarded.324