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
✍ Scribed by J. Podešva; J. Spěváček; J. Dybal
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 209 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
1 H nuclear magnetic resonance ( 1 H-NMR), 13 C-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 Յ 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 total hydrogenation of the olefinic double bonds of the polymeric substrate by diimide was observed.