Determination of Resorcinol Content in Phenol-Resorcinol-Formaldehyde Resins by Infrared Spectrometry

Twenty-six phenol-resorcinol-formaldehyde (PRF) resins with resorcinol contents ranging from 7.9% to 49.4% were studied by infrared spectrophotometry. An empirical relationship was found between the absorbance ratio of bands Aii4O/Ai22O and the resorcinol content. This technique used provided a fast and reliable estimation of resorcinol content on a weight-to-weight basis of added solids for the resins examined.