The graft polymerization of styrene onto silica gel in the presence of the silicone modifier γ‐methacryloxypropyl‐methyldiethoxysilane has been investigated. The main peculiarity of the styrene polymerization on silica gel in the presence of this modifier is the screening of the silica gel surface by the grafted polystyrene a t the very beginning of the reaction. The mechanism of the increase of the rate of styrene polymerization on the silica gel surface in the presence of the modifier is discussed.

The kinetic peculiarities of 1.4‐trans‐polymerization of isoprene with vanadium catalyst systems being activated by intermediate thermal treatment have been investigated. The rate propagation and chain transfer constants have been determined by two independent methods, namely by kinetic and radiochemical ones. It is supposed that the peculiarities of the polymerization on kinetic catalysts systems are connected with the formation of mixed crystal structures of vanadium and aluminium during the period of thermal treatment of the catalyst.

Die Copolymerisation von Isopren rnit ungesattigten polycyclischen Bruckenverbindungen (Norbornen,5, Methylennorbornen) in Gegenwart von TiC14/Al(i-C4H,), und VOC1,/AI(i-C4H,), wird untersucht. Es wurde festgestellt, daB Norbornadien-2,5 die hochstc und sein Dimer die niedrigste Reaktivitat aufweist. Zur Bestatigung der Bcsonderheiten der Copolymerisation von Kohlenwasserstoffen derartiger Struktur mit Dienen wurden quantenchemische Rechnungen und Untersuchungen der Photoelektronenspektren rnit herangezogen. 3asucuaocma peatcmusnocmu nenacbatqennbax noauyumurecxux coeaunenuii om ux cmpytcmypbz npu conoauaepuaayuu na tcama.mmuuectcux cucmeaax B pa6o~e H a y s a n a c b C O~O J I H M~~H~~~H H ~a o n p e~a c MOCTHKOBMMH n o n n q H K n m e c K n M n H e H a c b I u e H H m m coepxXHMHWCKHe P a C q e T b I EI AaHHbIe H3J"4eHHfi @OTOEUIeKTpOHHbIX CneKTpOB.Dependence of the reactivity of unsaturated polycyclic hydrocarbons on their structure at the complex-coordinative copolymerization with isoprene The copolymerization of isoprene with unsaturated polycyclic bridged compounds (norbornene, norbornadiene-2,5, norbornadiene-2,5 dimer, exo-dicyclopentadiene, endo-dicyclopentadiene and methylene norbornene) on the catalytic systems TiCl4/A1(i-C4Hg), and VOCl,/Al(i-C4Hg), is investigated. I t was established t h a t norbornadiene-2,5 reveals the highest reactivity while its dimer has the lowest one. Quantum-chemical estimations and photoelectron spectroscopic data are applied t o substantiate the characteristics of copolymerizing t h e mentioned hydrocarbons with the clicne.

organic chemistry, review organic chemistry, review Z 0200 20 -248 Reactivity of Lignin and Problems of Its Oxidative Destruction with Peroxy Reagents -[157 refs.]. -(DEMIN, V. A.; SHERESHOVETS, V. V.; MONAKOV, J. B.; Russ. Chem. Rev. (Engl. Transl.) 68 (2000) 11, 937-956; Inst. Org.

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