| Abstract: | A two‐level full factorial experimental design with three variables, formaldehyde‐to‐phenol (F/P) molar ratio, hydroxyl‐to‐phenol (OH/P) molar ratio, and condensation viscosity was implemented to determine the effect of the variables on the structure of phenol‐formaldehyde resol resins for paper overlay impregnation. Ten resins were prepared with F/P molar ratios between 1.9 and 2.3, OH/P molar ratios between 0.09 and 0.13, and condensation viscosities between 60 and 180 mPa s. The effect of these three independent variables on the chemical structure was analyzed by 13C‐NMR spectroscopy, on the molecular weight distribution by gel permeation chromatography, and on the reactivity by differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2942–2948, 2004 |
