view:25240 Last Update: 2018-10-20
Sohrab Rahmani, A.A. Entezami|
Preparation of tethered half-titanocene complex on cross-linked polystyrene beads for using in syndiospecific polymerization of styrene
تهیه کمپلکس نیمه ساندویچی تیتانوسن متصل شده برروی دانه های پلی استایرن کراسلینک برای استفاده در پلیمریزاسیون سیندیوتاکتیک استایرن
In this work the cross-linked polystyrene beads were functionalized with silyl hydride groups. Two synthetic procedures were employed to tether of indenyltrichlorotitanium (IndTiCl3) on the functionalized polystyrene beads. In one approach (method A), the half-titanocene catalyst bearing an allyl group (1-allylindenyltrichlorotitanium) was synthesized and covalently anchored on the functionalized polystyrene by using of hydrosilylation chemistry. In the second approach (method B), the half-titanocene complexwassynthesized on the functionalized polystyrene beads. The polymer-supported catalysts were tested for styrene polymerization using methylaluminoxane (MAO) as a cocatalyst. The obtained results revealed that the supported catalyst prepared with method (A) has higher catalytic activity and syndiotacticity than the supported catalyst obtained by method (B). In addition the scanning electron microscopy (SEM) images showed that the polymer particle replicates the shape of the carrier. Furthermore, the 13CNMR and differential scanning calorimetry (DSC) studies confirmed the high syndiotacticity of obtained polymers.