Hydrogenation of low-molar-mass, OH-telechelic polybutadienes. II. Nuclearmagnetic resonance and infrared spectrometric determination of hydroxyl end groups before and after hydrogenation by diimide

H-1 nuclear magnetic resonance (H-1-NMR), C-13-NMR, and infrared spectrosco pies were used to determine concentrations (c(OH), in mmol/g) of the second ary hydroxyl end groups in the low-molar-mass, OH-telechelic polybutadienes , and their hydrogenated analogs. Mean OH-functionality (f(OH) less than or equal to 2), that is, an average number of OH groups per one polymer chain , was calculated from c(OH) for each sample and each method, and the result s were compared with those obtained by a conventional acetic anhydride titr ation method. It has been found that with molar masses of the samples studi ed (2310 to 3410 g/mol), the differences between individual spectrometric m ethods are usually not higher than approximately 10%, which corresponds to an expected relative experimental error. Certain differences in f(OH) betwe en individual methods are discussed. No systematic change of f(OH) after vi rtually total hydrogenation of the olefinic double bonds of the polymeric s ubstrate by diimide was observed. (C) 1999 John Wiley & Sons, Inc.