Determination of hydroxyl number in aliphatic polyesters and polyethers using a colorimetric method

Hydroxyl number quantification is an important tool used in polymer science and practice. However, the standard method recommended for polyols, e.g. polyesters and polyethers, uses noxious chemicals that occasionally can cause hydrolysis of the polymeric material. Therefore, further procedures have been investigated as alternative techniques that can be useful in the polymer laboratory as routine. The aim of this paper was to develop and validate a sensitive colorimetric assay for determination of hydroxyl number in aliphatic polyesters and polyethers. This study was carried out for all validation parameters established by the international guidelines. Validation results on linearity, specificity, accuracy and precision were effectively performed. The reproducibility presented a relative standard deviation of 0.81. The proposed method is a simple, low cost and easy handling approach for the quantitative determination of hydroxyl number in aliphatic polyesters and polyethers.