Reversible-Deactivation Radical Polymerization (RDRP) Of Methyl Methacrylate With Organic Catalysts

The paper was mainly focused on the use of organic catalysts in Reversible-Deactivation Radical Polymerization (RDRP) of Methyl Methacrylate with In-Situ formed alkyl iodide initiator. The detailed information is as follows:1. The Reversible Complexation Mediated Polymerization (RCMP) of methyl methacrylate was carried out utilizing an alkyl iodide in-situ formed as initiator and Bu4N+Br- or Bu4N+I- as organic salts catalysts. Firstly, Bu4N+I- was higher catalytic reactivity than Bu4N+Br- as verified by the reaction mechanics and the resulted polymers. Secondly, the effect of Bu4N+I- contents on the controllability of methyl methacrylate polymerization was investigated in details. The results showed that the ratio [MMA]0:[I2]0:[AIBN]0:[BNI]0=100:0.5:0.75:0.25 is an optimum formula, affording resulted polymers with predetermined molar masses and molar mass dispersities values (Mw/Mn<1.27) at relatively high polymerization rate. Last, the structure of the obtained PMMA-I prepared by RCMP was characterized by 1H NMR spectrum. A good agreement between Mn,NMR and theoretical molar mass (Mn.th) of the polymer was observed and the fraction of iodine chain end of the low- molar-masses PMMA chains was 98.8%.2. The RCMP-solution of methyl methacrylate was carried out utilizing an alkyl iodide in-situ formed as initiator and Bu4N+I- as organic salts catalysts. Firstly, the effect of Bu4N+I- contents on the controllability of methyl methacrylate polymerization was investigated in details. The inhibition time can be significantly shortened and the polymerization rate may be accelerated by increasing the BNI concentration. Secondly, the polymerizations were performed at various temperatures (70?,75? and 80?) and a constant molar ratio of reagents ([MMA]0:[I2]0:[AIBN]0:[BNI]0=100:0.5:0.75:0.25). The rate of polymerization increased and the inhibition time can be significantly shortened at higher temperature. Polymers with slightly lower molar masses than predicted by the ratio ?[M]/[CP-I]0 were obtained at a later stage of polymerization at 75? and 80?. The structure of the obtained PMMA-I prepared by RCMP was confirmed by GPC and 1H NMR spectrum. We added fresh monomer (MMA) to the polymerization system offer 100% monomer conversion to conduct the chain-extension reaction. Last, in order to investigate the effect of solvents on the RCMP of MMA, the polymerizations were carried out in benzene, toluene, DMF, THF and acetonitrile (CH3CN). The results showed that all of the solvents which were considered in this paper gave a reasonable control of the final molar mass, indicating that RCMP is a rather robust and flexible process.3. The RCMP of methyl methacrylate was carried out utilizing an alkyl iodide in-situ formed as initiator and TEAI as organic salts catalysts. Firstly, the effect of TEAI contents on the controllability of methyl methacrylate polymerization was investigated in details. The inhibition time can be significantly longer and the polymerization rate may be retarded by increasing the TEAI concentration. Secondly, the polymerizations were performed at various temperatures (70,80, and 85?) and a constant molar ratio of reagents. The rate of polymerization increased and the inhibition time can be significantly shortened with higher temperature. Polymers with slightly lower molar masses than predicted by the ratio ?[M]/[CP-I]o were obtained at a later stage of polymerization at higher temperature (85?). Furthermore, the structure of the obtained PMMA prepared by RCMP was characterized by 1H NMR spectrum. A good agreement between Mn-NMR and theoretical molar mass (Mn.th) of the polymer was observed and the fraction of iodine chain end of the low-molar-masses PMMA (2000-4000 g/mol) chains was 99%.