MICROSTRUCTURE DETERMINATION OF STYRENE BUTYL ACRYLATE COPOLYMERS BY NMR-SPECTROSCOPY

Styrene butyl acrylate (S/B) copolymers of different composition were prepared by bulk polymerization using a free radical initiator. Copolymer composition was determined from NMR spectra and monomer reactivity ratios were calculated using the nonlinear least square Error-in-Variable method (EVM). Copolymerization parameters such as triad concentrations, conditional probabilities and number-average sequence lengths in the copolymers were calculated from (C{H})-C-13-H-1 NMR spectra. The observed triad sequence concentrations as determined from (C{H})-C-13-H-1 NMR spectra were in good agreement with those calculated from the reactivity ratios. Coisotacticity parameter (sigma) has been calculated from NMR spectroscopy using oxymethylene resonance signal in H-1 NMR spectra.