Comonomer Effects of High a-Olefins in Metallocene Catalyzed Terpolymerization: Thermal Properties

Abstract

A range of polymers were synthesized using a rac-Et(Ind)2ZrCl2 catalyst and methylaluminoxane co-catalyst system. The polymers, homo-, co-and terpolymers were comprised of ethylene, 1-decene and p-methyl styrene. The structures and compositions of the polymers were examined by 13 C nuclear magnetic spectroscopy and 1 H nuclear magnetic spectroscopy. The catalytic activity, weight-averaged molecular weight, number-averaged molecular weight and molecular weight distribution of the polymers were characterized. The glass transition temperature, melting temperature, crystallization temperature, crystallinity, storage modulus, loss modulus and tan δ of the terpolymers according to the 1-decene feed molar concentration were also examined. compared with the thermal properties of the terpolymers, focusing on the comonomer effects of 1-decene. EXPERIMENTALAll manipulations were carried out in an inert nitrogen atmosphere. High-purity grade ethylene gas (Dae-myung Gas Co.) was used after passing it through an alumina/zeolite column. 1-Decene (Aldrich, 94 %), n-hexane (SAMCHUN, 99.5 %) and toluene (SAMCHUN, 99.5 %) were purified by heating them over sodium under reflux, using benzophenone as an indicator and stored in a dry box. A solution of rac-Et(Ind) 2 ZrCl 2 (Sigma Aldrich) in toluene was also prepared. p-methyl styrene (p-MS) was distilled under reduced pressure in the presence of CaH 2 after performing the standard purification procedure. The specimens for thermal and wide-angle X-ray scattering analyses were prepared by compression molding in a hot press. Typically, all the polymerization reactions were carried out in a 300 mL stainless steel autoclave with a mechanical stirrer.After saturating the autoclave with ethylene gas, polymerization was initiated by injecting the required amount of the monomers, catalyst solution and methylaluminoxane (MAO). After several minutes, the polymer solution was poured into a diluted HCl/EtOH solution. The resulting polymer was washed with EtOH (600 mL) and dried in vacuo.