1H- and13C-NMR Studies on Phenol-Formaldehyde Prepolymers for Tannin-Based Adhesives

Abstract
The number average structure and the molecular weight distribution of phenol-formaldehyde prepolymers for use in synthesis of tannin-based adhesive resins were determined with 1H- and 13C-NMR spectroscopy and gel permeation chromatography of acetylated resins. These methods were used to determine differences in phenol-formaldehyde prepolymens prepared under different reaction conditions. Quantitative 13C-NMR techniques provided a detailed analysis of the structure of a phenol-formaldehyde prepolymer.