Polymerization With Metal-free Organic Catalyst

We have systematically studied the synthesis of polymers with metal-free organic catalysts, such as trifluoromethanesulfonimide,1,8-diazacyclo-[5,4,0]undec-7-ene,1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis [tris(dimethylamino) phophoranylidenamino]-2A5,4A5-catenadi(phosphazene) in this thesis. Polymers based on vinyl ether,l-lactide and4-vinylbenzyl methacrylate have been prepared with those organic metal-free catalysts proceeding controlled/living cationic polymerization, ring-opening polymerization and controlled/living anionic polymerization respectively. The polymerization kenetic, mechanism and some other properties have also been studied. The results are as follows:1) We have synthesized narrowly distributed poly(isobutyl vinyl ether)(PIBVE) with trifluoromethanesulfonimide (HNTf2) as initiating system, experiments demonstrated that the polymerization was in a controlled manner. The HNTf2could be an initiator, an activator or a stabilizer in this initiating system and the polymerization was conducted in a fast and facile process without base-assisting. Nuclear magnetic resonace (NMR) and differential scanning calorimetry (DSC) measurements were used to study the properties of the polymers.2)By using1,8-diazacyclo-[5,4,0]undec-7-ene (DBU) as both the atom transfer radical polymerization (ATRP) ligand and ring-opening polymerization (ROP) catalyst, we have combined copper-catalyzed ATRP and organo-catalyzed ROP in one-pot, and successfully synthesized poly(l-lactide)-b-poly(methyl methacrylate)(PLA-b-PMMA) diblock copolymers. The structure of the block copolymers is confirmed by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and laser light scattering (LLS).3) We have synthesized poly(4-vinylbenzyl methacrylate)(PVBMA) with l-tert-butyl-4,4,4-tris (dimethylamino)-2,2-bis [tris (dimethylamino) phophoranylidenamino]-2A5,4A5-catenadi(phosphazene)(t-BuP4) as the catalyst. The selective polymerization of two different double bond was acheived, and we also have investigated the cross-linking properties of polymers through nuclear magnetic resonace (NMR),differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements.