Characterization of poly(vinyl alcohol‐co‐vinyl acetate) by the iodine complexation method

Analysis of sequence distribution (SD) in poly(vinyl alcohol‐co‐vinyl acetate) (p(VA‐VAc)) by the iodine complexation method (ICM) was investigated through the formation of a red complex of p(VA‐VAc) with iodine‐iodide. Differential thermal analysis (DTA) has been known to be a measure of SD and the ICM was also suggested to be valid for the SD analysis. ICM can be applied for samples of p(VA‐VAc) rich in VAc‐unit content, in which DTA could not be used. Results of SD analysis on p(VA‐VAc) by 1 NMR spectra were compared with those from ICM, and excellent agreement was found between data. The ICM can be applied as a convenient screening method for SD of p(VA‐VAc) as far as the red‐complex formation is concerned, and was shown to have much wider applicable range than the DTA method.