ACRYLONITRILE ACRYLIC ACIDS COPOLYMERS .1. SYNTHESIS AND CHARACTERIZATION

Acrylonitrile (AN) was copolymerized with acrylic acid (AA), methacryl ic acid (MAA), and itaconic acid (IA) by the aqueous suspension method at 40-degrees-C with ammonium persulfate and sodium metabisulfite as the redox initiator. The reactivity ratios for the AN-AA and AN-IA sys tems were also calculated by the Finemann-Ross and the Kelen-Tudos met hods. Higher r2 (AA) for the AN-AA system in comparison to r2 (IA) for the AN-IA system indicates greater reactivity of AA toward the propag ating species. The influence of comonomers on intrinsic viscosity, tac ticity, and number-average sequence lengths was studied. C-13-NMR spec tra revealed that AN copolymers having approximately 2 mol % of AA hav e a greater percentage (> 30%) of isotactic content than of homopolyac rylonitrile. Tacticity has also been calculated from infrared spectra of the polymers using stereospecific absorption bands at 1250 and 1230 cm-1. (C) 1993 John Wiley & Sons, Inc.