Atom Transfer Radical Polymerization of Methyl Acrylate, Methyl Methacrylate and Styrene in the Presence of Triethanolamine Efficient Accelerator
Transition metal-mediated atom transfer radical polymerization (ATRP) is a type of "living"/controlled radical polymerization. Recently, there has been increasing focus on reducing the high cost of catalyst isolation and post-polymerization purification in ATRP. In this work, it was found that triethanolamine significantly enhanced CuBr/N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (CuBr/TPEN) and CuBr/tris[2-(dimethyl Amino) ethylamine] catalytic performance (CuBr/Me6TREN). Addition of 25-fold molar amount of triethanolamine relative to CuBr significantly reduced the catalyst loadings of CuBr/TPEN and CuBr/Me6TREN from a catalyst-to-initiator ratio of 1 to 0.01 and 0.05, respectively. Polymerization of methyl acrylate, methyl methacrylate, and styrene in the presence of triethanolamine still exhibits first-order kinetics and produces poly(methyl acrylate), poly(methacrylic acid) with molecular weights close to theoretical values and low polydispersity methyl ester) and polystyrene. These results suggest that triethanolamine is a highly efficient and versatile ATRP promoter with potential industrial applications.
It was found that triethanolamine significantly enhanced the catalytic performance of CuBr/TPEN and CuBr/Me6TREN, and significantly increased the polymerization rates of methyl acrylate, methyl methacrylate, and styrene in ATRP catalyzed by both catalysts. Correspondingly, in the presence of triethanolamine as a promoter, the catalyst loading of CuBr/TPEN and CuBr/Me6TREN can be reduced by up to 100-fold and 20-fold, respectively. methyl acrylate
Statistical (random) copolymers of acrylonitrile (AN) and methyl acrylate (MA) have been synthesized by free-radical homogeneous (solution) and heterogeneous (suspension) methods. The selected compositions can be fabricated by environmentally friendly, solvent-free melt spinning and are of great interest as precursors of carbon fibers. The dynamic and steady state melt viscosities of these copolymers were studied as a function of molecular weight and copolymer composition. Melt processability at 200–220 °C depends on the copolymer composition and also on the molecular weight, which is controlled by the chain transfer agent concentration and reaction temperature. Controlled molecular weight copolymers containing 10 mole percent or more of methyl acrylate exhibit good melt processability, which can be further enhanced by stabilizers. This thermoplastic behavior is supported by a significant temperature increase caused by the cyclization exotherm. Thermal analysis (differential scanning calorimetry, dynamic mechanical analysis) further revealed that the comonomer retards cyclization, allowing thermoplastic processing.