Study on the copolymerization of propylene with norbornene using metallocene catalysts

The copolymerization of propylene with norbornene, using the metallocene catalysts Me2Si(2-Me-Ind)(2)ZrCl2 and Ph2C(Flu)(Cp)ZrCl2 was evaluated. The presence of norbornene decreases the polymerization activity in both systems. In the Me2Si(2-Me-Ind)(2)ZrCl2 system, the decrease is ca. 80 % using 0.5 mL of norbornene while the addition of 2 mL reduces the activity by 97 %. The molecular weight of the materials decreases between 27,000 and 37,000 g/mol in the presence of norbornene. The Ph2C(Flu)(Cp)ZrCl2/MAO system has the same tendency, but the norbornene has a lesser effect on the activity, with 2 mL of comonomer reducing the activity ca. 80 %. The molecular weight decreased significantly with this system as well. The elongation at break of some of the materials was 80 times higher than the homopolymer and the Young's modulus slightly superior to the homopolymer. This indicates that it is possible to generate materials that keep the properties of a syndiotactic polypropylene but with good elastomeric properties.