Ansa-metallocene catalyst based on 3-phenyl and 4-methyl substituted: catalyst evaluation in conjugated and non-conjugated diene polymerization

In this contribution, we describe the kinetics associated with the rac-Me2Si[2-Me-4-Ph-Ind](2)ZrCl2 (Cat-1)/borate/TIBA catalyzed copolymerization of E/dienes (isoprene (IP), butadiene (BD), 5-ethylidene-2-norbornene (ENB), 4-vinylcyclohexene (VCH) and vinyl norbornene (VNB)), and E/diene/1-hexene (1H) terpolymerization by using thiophenecarbonyl chloride (TPCC) that was used in Ziegler-Natta (Z-N) and metallocene-catalyzed polyethylene (PE) and polypropylene (PP) and E/P polymerizations. In both types of polymerizations, a higher amount of dienes was incorporated when VNB (2.70 mole %) and VCH (1.56 mole %) were added as comonomer, but IP and BD were incorporated with the moderated rate (0.6-1.1 mole %) with higher activities (3.45x10(6)gm/mmol(Mt)& BULL;h). The active center [Zr]/[C*] fraction is higher (61%) than previously reported PE polymerizations, especially in the case of E/IP, E/BD and E/IP/1H but lower than E/P (87%) copolymerization. Significantly, IP and BD activated the inactive catalytic sites that were dormant in the PE. The propagation rate constant (k(p)E) with IP was higher (k(p)564 Lmol(-1)s(-1)), while k(p)E with VNB (k(p)379 Lmol(-1)s(-1)) and VCH (k(p)304 Lmol(-1)s(-1)), which were lower than PE. This difference is built because of the diffusion barrier in the system. Compared to E/diene copolymers, k(p)E values in E/diene/1H terpolymerizations for IP, VCH, and VNB are higher and stable except ENB and determine that 1H prevents the insertion of dienes and reduces the crystalline properties resultant moderate k(p)E. Even though the E/BD copolymers decreased butadiene content of over 2 mol% resulted in better crystalline characteristics, lower diffusion barriers, and a higher k(p)E value. In concept, IP and BD are linear and readily available for coordination. While VCH, ENB and VNB are cyclic and bulky, metallocene in contact ion pairs cannot accept ENB, VNB, and VCH for coordination and subsequently act as dormant in the polymerization.

Automated summary

In this study, the kinetics of the copolymerization of E/dienes and the terpolymerization of E/diene/1-hexene using Cat-1/borate/TIBA catalyst were described. The addition of VNB and VCH as comonomers resulted in a higher incorporation of dienes, while IP and BD were incorporated at a moderate rate. The fraction of active centers [Zr]/[C*] was higher than in PE polymerizations but lower than in E/P copolymerization. IP and BD activated dormant catalytic sites in PE. The k(p)E values in E/diene/1H terpolymerizations were higher and stable, except for ENB, suggesting that 1H hindered the insertion of dienes and reduced the crystalline properties. A higher k(p)E value was observed when the butadiene content in E/BD copolymers exceeded 2 mol%. The bulky nature of VCH, ENB, and VNB prevented their coordination with the metallocene catalyst.