How to does calculate Mole ratio of Resol resin?
Answers
Resol type phenolic resins (mole ratio F/P = 0.72.5) were prepared in the presence of caustic soda, and their infrared spectra were examined. It was found that intensities of 1610, 1150 and 890 cm-1 bands varied with mole ratio and their change with reaction time was neglegible.
Each sample was evacuated to remove water and methanol, and the infrared spectrum was measured as liquid film on NaCl plate. The calculation of intensities was done by absorbance ratio method taking that of 1590cm-1 band as the reference to compensate the film thickness.
Commercial samples varying with mole ratio, kind of catalyst, reaction temperature, reaction time etc., were examined about the relation between absorbance ratio and mole ratio, and it was found that the mole ratio was able to be determined by this method with standard deviation 0.10.2 (as F/P)