Methyl Imidazole Organic Acid Ionic Liquid In The Atrp Of Sio <sub> 2 </ Sub> / Pmma Hybrid Materials Preparation

Atom transfer radical polymerization of methyl methacrylate (MMA) has been conducted successfully in a series of N-methylimidazolium carboxylate ionic liquids. The effect of polymerization temperature, reaction time and ratios of reactants on the kinetics of ATRP, molecular weight and molecular weight distribution of polymer was investigated. The apparent rate constants (kapp.) under different conditions were calculated. The effect of the anions of ionic liquids on the polymerization was also discussed in this paper. Furthermore, the chain extension with MMA and block copolymerization with St, MA employing bromine atom ended PMMA as the macroinitiator was carried out in ionic liquids, and the copolymer with much narrower PDI (Mw/Mn =1.06) was obtained. Finally, organic/inorganic hybrid composite PMMA/SiO2 was prepared utilizing this method. This paper mainly consisted of the following contents:1. The polymerization of MMA in the presence of FeCl3 or CuBr as catalyst was carried out in [Hmim][HCOO] ionic liquid. The polymerization employing FeCl3 as the catalyst can proceed without additional initiator and ligand, but the PDI values were broad and the system was less controlled. The ATRP of MMA employing ethyl 2-bromoisobutyrate (EBiB)/CuBr as the initiating system can be conducted under lower temperature. The PDI values of polymers were narrow (e.g. Mw/Mn=1.20) despite no ligand and organic solvents used. The results confirmed the high reaction rate and the"living"/controlled characteristic.2. The ATRP of MMA employing ethyl 2-bromoisobutyrate (EBiB) /CuCl or EBiB/CuBr as the initiating system was investigated in [Hmim][CH3COO], respectively. The linear first-order kinetic relationship, the increasing molecular weights with time and the narrow PDI of PMMA confirmed the"living"/controlled characteristic of the two systems. Furthermore, the effect of initiator was investigated for the ATRP employing EBiB/CuBr as the initiating system. For the EBiB/CuCl system, the effect of temperature was studied,and the chain extension with MMA and block copolymerization with St and MA were conducted successfully.3. The ATRP of MMA was investigated in three ionic liquids, N-methylimidazolium acetate ([Hmim][CH3COO]), N-methylimidazolium propionate ([Hmim][CH3CH2COO]) and N-methylimidazolium butyrate ([Hmim][CH3CH2CH2COO]), respectively, with EBiB/CuBr as the initiating system. The order of the apparent polymerization rate constants was kapp([Hmim][CH3COO]) > kapp([Hmim][CH3CH2COO]) > kapp([Hmim] [CH3CH2CH2COO]), indicating a strong dependence of reaction rate on the length of the substituted groups of anions in the ionic liquids. The PDI values of the polymers obtained via atom transfer radical polymerization became much narrower in [Hmim][CH3CH2CH2COO] while the rate of the reaction was lower. The copolymer with narrow PDI (Mw/Mn=1.06) was obtained via block copolymerization with St.4. Primary investigation on the synthesis of the hybrid material PMMA/SiO2 utilizing ATRP method in [Hmim][CH3COO] was conducted.