A Study on the Copolymerization Kinetics of Phenylethyl Acrylate and Phenylethyl Methacrylate

Copolymers of phenyl alkyl acrylates/methacrylates are used clinically as soft materials for the foldable intraocular lens (IOL) to treat cataracts. In this study, copolymers of 2-phenylethyl acrylate (PEA) and 2-phenylethyl methacrylate (PEMA) of various compositions were prepared using free radical polymerization in solution. The composition of the copolymers was determined by H-1-NMR analysis. The reactivity ratios of the monomers were calculated using the conventional Fineman-Ross or Kelen-Tudos method. The reactivity ratio of PEA (r(1)) and PEMA (r(2)) were estimated to be 0.280 and 2.085 using the Kelen-Tudos method, respectively. These values suggest that PEMA is more reactive in copolymerization than PEA, and the copolymers will have a higher content of PEMA units. The glass transition temperature (T,) of the copolymers increased with increasing PEMA content. The molecular weight and polydispersity indices (M-w/M-n) of the polymers were determined by GPC. Overall, these results are expected to be quite useful in applications to foldable soft IOL materials.