Determination of %Polyvinyl Alcohol in Vinyl Acetate-Alcohol Resins by Quantitative Near Infrared Spectroscopic Analysis

A number of vinyl acetate-alcohol resins (VAAR) samples were collected during partial hydrolysis of poly(vinyl acetate) at different conversions levels (<30%). Using these VAAR samples with known OH (hydroxyl) content, it has been demonstrated that near infrared (NIR) spectroscopic data produced a near perfect fit for the calibration of OH content. A 4-factor partial least-squares method was employed and gave the best results. Further work also confirmed that NIR, operating at a well-controlled environment, is able to quantify, with great precision, the OH content of the selected model compound. In the case for the OH content analysis of VAAR resins, solvent mix ratio (methyl acetate: methanol) and temperature have been identified to be the two most influential factors on the analytical results. (C) 2010 Wiley Periodicals, Inc. Ads' Polym Techn 29: 1-10, 2010; Published online in Wiley Inter Science (www.interscience.wiley.com). DOI 10.1002/adv.20166