Complex-catalyzed Polymerization Of Water-soluble Monomers

On the dark the radical polymerization of water-soluble monomers (AM, AA and AMPS), which is initiated by FeCl3, is confirmed by our experiment and NMR results. Based on these experiment results, we have examined the interaction between FeCl3 and monomers, and the initiation mechanism. In the absence of light, FeOH2+, the hydrolysis product of FeCl3, forms identate-liganded complex with double bonds of monomers. The structure of the complex is determined by pH value and monomer concentration. There exist limits of pH value and monomer concentration. Out of the limits there is no polymer obtained. The kinetic results show that the complex HOFeAMCl2 acts as a catalyst. It reacts with an AM monomer to form the complex HOFe(AM)2Cl2. Then the complex HOFe(AM)2Cl2 releases its second AM monomer and forms free radical which has two active centers. The initiation mechanism is in fact a kind of complex-catalyzed polymerization. The polymerization mechanism is proved to be free radical polymerization by DPPH reagent.Through adjusting either FeCl3 concentration or monomer concentrations, we can change the effective complex content, and then control the polymerization process. FeCl3 concentration is usually excessive under normal conditions. The sole variable in the polymerization of a given sample is its monomer concentrations. The monomer order was found to be 1.0 for the initiation rate and 2.0 for the propagation rate. At the beginning of the reaction, the polymerization is very stable because that the monomer concentration have a little change. Through consumption of a little monomer, there is no influence of inhibitor on the reaction and polymerization is very easy to be done.The initiation activation energy is 80.5kJ/mol, and its propagation activation energy is 58.26kJ/mol. Being lower initiation activation energy, polymerization can be processed at room temperature. But the polymeric rate is very slower. The relatively high propagation activation energy is due to its monomers participating in forming complex.