Synthesis of Poly(glycidyl Methacrylate-r-photochromic Monomer) by ATRP

The preparation of the random photochromic copolymer poly(glycidyl methacrylate-r-1'-(2-methacryloxyethyl)-6-nitro-3',3'-dimethylspiro-[2H-1]-benzopyran-2,2'-indoline) by ATRP is reported, which can be used for the preparation of smart materials. Narrow homopolymers obtained from glycidyl methacrylate (GMA) are prepared when HMTETA-copper bromide and ethyl 2-methyl-2-bromo-propionate are used as the catalytic system with methyl-ethyl-ketone at 50C. By using a molar ratio of 1:1 ligand:initiator, good correlations between experimental and theoretical molecular weights and narrow molecular weight distribution are obtained. These experimental conditions are also employed for the copolymerization of GMA with a photochromic monomer, where again good control of the polymerization reaction is obtained. The copolymer is fully characterized by spectroscopic techniques. The reactivity ratios are calculated according to the extended Kelen-Tudos method, while the composition of the copolymer is calculated by NMR. Determination of rGMA and rPHM gives a value of 0.985 for GMA and 0.596 for the photochromic monomer.