Hydrogenation of Low-Molar-Mass,OH-Telechelic Polybutadienes.II.Nuclear Magnetic Resonance and Infrared Spectrometric Determination of Hydroxyl End Groups Before and After Hydrogenation by Diimide

摘要

~1H nuclear magnetic resonance (~1H-NMR),'~(130C-NMR,and infrared spectroscopies were used to determine concentrations (c_(OH),in mmol/g) of the secondary hydroxyl end groups in the low-molar-mass,OH-telechelic polybutadienes,and their hydrogenated analogs.Mean OH-functionality (F_(OH) <=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 results were compared with those obtained by a conventional acetic anhydride titration method.It has been found that with molar masses of the samples studied (2310 to 3410 g/mol),the differences between individual spectrometric methods are usually not higher than approximately 10%,which corresponds to an expected relative experimental error.Certain differences in F_(OH) between individual methods are discussed.No systematic change of f_(OH) after virtually hydrogenation of the olefinic double bonds of the polymeric substrate by diimide was observed.