NEW POLYOLEFIN ELASTOMERS CONTAINING "REACTIVE" p-METHYLSTYRENE UNITS: PREPARATION BY METALLOCENE CATALYSTS

This paper summarizes the experimental results of three new polyolefin elasLumers, i.e., poly(l-octene-co-pmethylstyrene (O-p-MS), polyfethylene-ter-propylene-ler-p-methylstyrene) (EP-p-MS) and polytethylenc-tcr-l-octeneter-p-mcthylstyrene) (EO-p-MS), containing "reactive" p-MS units. Both Ziegler-Nalla and metallocene catalysts were used in studying co- and ter-polymerization reactions. In the cupolyinerization of I-octenc and p-MS, Ziegler-Natta catalyst TiCl3/AlEt3 exhibits higher catalyst reactivity to produce high molecular weight O-p-MS copolymers, containing up to 20 inol % p-MS. However, the copulymers show very broad composition and molecular weight distributions. On the other hand. two EP-p-MS and EO-p-MS tcrpolymers with narrow molecular weight and composition distributions were prepared by [C5 Me4(SiMe2N^t Bu)]TiCl2 metallocene catalysl with constrained ligand geometry. The sharp glass transition temperature (Tg) with flat baseline in each differential scanning calurimelry (DSC) curve indicates homogeneous terpolymer microstructures. The Tg of EP-p-MS is very sensitive to the terpolymer composition (ethylene/propylene ratio and p-MS content). In the compositions with ideal ethylene/prupylene ratio ~ 55/45, the Tg is almost proportional to the content of p-MS. Only with the concentration of p-MS < 2 mol %, docs the RP-p-MS show a low Tg < -45 °C. On the other hand, the EO-p-MS system exhibits a low Tg < -50 °C in a wide range of copolynier compositions, even ones with relatively high p-MS contents (> 7 mol %).