EFFECT OF ACRYLONITRILE-N-VINYLPYRROLIDONE COPOLYMERIZATION SYSTEMS ON MONOMER REACTIVITY RATIOS

Effect of different acrylonitrile N vinylpyrrolidone free radical copolymerization systems on reactivity ratios for monomers has been studied. The valoues of reactivity ratios were calculated by the method of Kelen Tudos. It shows that reactivity ratios in aqueous suspension polymerization system are similar to those in solution polymerization system when the conversion is less than 18%. As the conversion increases, the results are very different. H 2O/DMSO mixture solvent was also used for producing the AN NVP copolymer. In water rich reaction medium( m H 2O / m DMSO =60/40), reactivity ratios are equivalent to those in aqueous suspension polymerization system. With an increase of polarity of solvent, both r AN and r NVP reduce. When the reaction temperature rises, reaction gradually changs to ideal copolymerization.