| abstract |
This invention relates to analytical chemistry, in particular, to methods for determining free isocyanate groups. The aim of the invention is to increase the accuracy and reduce the duration of the determination of free isocyanate groups in the presence of compounds with blocked isocyanates. pami The method is carried out as follows: the analyzed sample is treated with an excess of secondary amine for 5–45 s, after which the solution is diluted with an organic solvent — lower aliphatic alcohol or acetone. Then a few drops of the indicator are added and titrated with a 0.1 M hydrochloric acid solution. before the blue color turns to straw yellow. At the same time, the control experiment was carried out with the same reagents, but without weighing the product. Make two parallel. definitions and finding the content of free isocyanate groups. The determination error does not exceed 10% i t table. W |