Investigation of the polymerization process and property modification of metallocene-bad cycloolefin copolymers (COC) shows that this monomer-catalyst combination enables synthesis of a new class of transparent thermoplastic polymers. Metallocene catalysis offers much opportuNty to v"y the composition and microstructure of the copolymers. The breadth of the polymer spe-ctwrn which can be hrther widened by polymer modification enables many applications for this new class of thermoplastics. The key parameters that control structure and properties in the COC family are discussed in this paper. ZUSAMMENFASSUNC Untersuchungen wesentlicher Aspekte der Polymerisation und der Eigenschallsmodifikation aufMetallocen-Katalyse basierender Cycloolefin-Copolymere (COC) zeigen, dal3 mit dieser Monomer-Katalysator-Kombination eine neue Klasse transparenter Thermoplasten Prghglich gemacht wird. COC konnen mit Metallocenen in beliebiger Zusammensetzung und mit kontrollierter Mikrostruktur hergestellt werden. Die somit erreichte und durch zusittzliche Modifikationen noch enveitehare Breite des Eigenschaftsspektrums erm6glicht Vielfllltige Anwendungen dieser neuen Polymerklasse. Die wichtigsten Schliisselfaktoren i m rohstofflich-technologischen Bereich, die diese Struktur-und Eigenschaftsvielfalt ergeben, werden beispielhaft beschrieben.

The Heck reaction allows the synthesis of monomers in a one-step reaction. Catalyzed by Pd, bromoarenes are reacted with ethylene to form substituted styrenes and symmetrical stilbenes. Unsymmetrical stilbenes are obtained from substituted bromoarenes and styrenes. Substituted hydroquinones and terephthalic acids are also available in high yields. Poly(l,4-phenylenevinylene) is obtained starting from 4-bromostyrene. Experimental partA typical procedure for the synthesis of a styrene and a stilbene derivative is given. Experimental conditions for other monomers are shown in Tab. 1.Reagents: DMF: distilled over 4,4 '-methylenedi(pheny1 isocyanate) and dibutyltin dilaurate as catalyst. Pd(OAc)2: used as received (Degussa). Tri-o-tolylphosphine: synthesized according to lit. '). Triethylamine, tributylamine: distilled over KOH. Styrene: used as received (stabilized with catechol). 4-Vinylbenzamide (6):A flame-dried pressure vessel of 100 ml volume was loaded under argon with 7 g (35 mmol) of p-bromobenzamide, 0,21 g (0,7 mmol) of tri-o-tolylphosphine, 0,078 g (0,35 mmol) of palladium acetate, 5,46 ml (40 mmol) of triethylamine, and a teflon@coated stir bar. 60 ml of DMF were added and a pressure of 72 bar ethylene (room temperature) applied. The autoclave was heated to 130°C for 24 h. The reaction mixture was precipitated with 400 ml of water and the solid dissolved in acetone. The filtered solution was concentrated and the residue was purified by sublimation. Yield: 3,7 g (72%), m.p. 176-177 "C, determined by DSC (lit.5): 170°C).