INFLUENCE OF THE POLYMERIZATION CONDITIONS ON THE RIGIDITY OF PHENYLNORBORNENE-ETHYLENE COPOLYMERS MADE USING ETHYLENE BIS (INDENYL) ZIRCONIUM DICHLORIDE AND MAO

When characterized with DMA it was found that Phenylnorbornene - ethyl ene copolymers with equivalent comonomer concentrations had very diff erent storage moduli in the glassy state as well as glass transition t emperatures. NMR analysis of the copolymers revealed that they had dif ferent ratios of Exo- and Endo-diastereomers even if the same comonome r composition had been used. The Exo/Endo-ratio in the polymer was sur prisingly higher than in the monomer and increased with higher incorpo rations of the comonomer. Copolymers with higher Exo/Endo-ratios also had a tendency for lower storage moduli in the glassy state and higher tan delta peaks. These properties are valuable because more flexible and impact-resistant copolymers are obtained. (C) 1998 John Wiley & So ns, Inc.