view:24702 Last Update: 2018-10-20
Sohrab Rahmani and A. A. Entezami|
Preparation of Tethered Half-Titanocene Complex on Syndiotactic Poly (styrene-co-p-methylstyrene) for Usingin Syndiospecific Polymerization of Styrene
تهیه کمپلکس نیمه ساندویچی تیتانوسن متصل شده برروی کوپلیمر سیندیوتاکتیک استایرن-پارامتیل استایرن برای استفاده در پلیمریزاسیون سیندیوتاکتیک استایرن
In this work the syndiotactic polystyrene copolymer, poly (styrene-co-p-methylstyrene) was prepared by the copolymerization of styrene and p-methylstyrene with cyclopentadienyltitanium trichloride/methylaluminoxane catalyst. This copolymer was functionalized with silylhydride groups. The structure of copolymer and functionalized copolymer were characterized by FT-IR, 1H-NMR and 13C-NMR spectroscopy. The obtained results revealed that the functionalization reaction successfully proceeds at low temperatures. Tethering of half-titanocene complex on polymeric support was done by the hydrosilylation reaction of 1-allylindenyltrichlorotitanium with silyl-hydride functionalized copolymer in the presence of Karstedt catalyst as a coupling reagent. The polymer-supported catalyst was tested for syndiospecific polymerization of styrene using methylaluminoxane as a cocatalyst. The results of styrene polymerization showed that the polymer-supported catalyst exhibited high activity for syndiospecific polymerization of styrene. The polymer prepared with supported catalyst was characterized by carbon nuclear magnetic resonance (13C-NMR) and differential scanning calorimetry (DSC). The results confirmed the syndiotacticity of obtained polymers. X-ray diffraction (XRD) analysis showed the δ-form crystalline structure of obtained syndiotactic polystyrene.