Syntheses Of Early Transition Metal Based Post Metallocene Catalysts For Aqueous Emulsion Polymerization Applications

Abstract

The syntheses of five new catalytic systems [TiLCl2] {LH2=2-(3,5-Di-tert-butyl-2-hydroxybenzylamino)-succinic acid} (Complex 1), [TiLCl2] {LH2=2-(2, 4-di-tert-butyl-6-hydroxybenzyl amino acetic acid)} (Complex 2), and Titanium (IV) complexes with oxalic, malonic and succinic acid [TiL2Cl2] {LH= oxalic (Complex 3), malonic (Complex 4) and succinic acid (Complex 5)} bearing N and O as a pendant donor and examined for the homo-polymerization of MMA and styrene at ambient temperature. Upon activation with NaBPh4, the complexes are found to exhibits highly active for the polymerization of MMA even at very low co-catalyst /catalyst ratios. The effect of ring size of synthesized complex on polymerization activity was also observed. Also, synthesized complexes and polymers are characterized by different instrumental techniques including 1H NMR, 13C NMR, UV-visible, IR, HRMS, DSC, DLS, XRD, TGA and GPC analyses. The results described that the synthesized new complexes are able to produce syndiotactic rich PMMA and polystyrene and in some cases produce isotactic PMMA with high molecular weights. kinetic parameters like activation energy and rate constant for PMMA, are also determined and Eapp value, which is found to be 58.842 kJ mol-1. Moreover, for identifying the best combination of catalyst, co-catalyst and monomer ratio, response surface methodology has been adopted. newline