Novel Catalyst Systems For Atom Transfer Radical Polymerizations

This thesis mainly discussed the applications of ferrous chloride and other metal chloride catalytic systems in the atom transfer radical polymerization (ATRP) of MMA. It consisted three parts:1. A new kind of multiamine ligand N,N,N',N",N"-penta(methyl acrylate) diethylenetriamine (MA5-DETA ) was found to be an ideal ligand of ferrous chloride or ferric chloride. In previous literature, multiamine ligands were widely used as the ligand of Cu for ATRP, but their uses in Fe-based ATRP were none. We found the RATRP of MMA catalyzed by AIBN/ FeCl3-6H2O/ MA5-DETA and ATRP of MMA catalyzed by ethyl 2-bromoisobutyrate (EBiB)/ FeCl2-4H2O/ MA5-DETA were both showed well-controlled manner, especially in the RATRP, the catalystic activity of FeCl3'6H2O/ MA5-DETA were high. The preparation of MA5-DETA was easy and the yield was high, besides it was nontoxic, so it was a promised ligand for Fe-based (R)ATRP.In order to improve the controllability of the above ATRP, additive was added to the polymerization system. The addition of a certain amount of FeCl3-6H2O as the additive into the above system resulted in the decrease of the polymerization rate and the improvement of the controllability.SnCl2-2H2O was not a kind of transition metal and it beyond the nine ATRP catalyst metals. But we found that SnCl2-2H2O coordinated by MA5-DETA can catalyst the ATRP of MMA with the existence of FeCl3-6H2O as additive. In this novel catalyst system, the effect of SnCl2-2H2O was only reacted with EBiB to produce radicals in the initiation stage, the real atom transfer was established between Fe(II) and Fe(III). The catalyst mechanism was different from normal ATRP or RATRP.