Laser Raman spectral study of resol formation

Abstract

SynopsisLaser Raman spectroscopy was used to monitor changes in the substitution pattern during the formation of a phenol-formaldehyde resin (resol). The substitution-sensitive bands were identified and their relative intensities related to molecular weight of the resol. Results of this study are similar to those obtained by previous workers in the field using paper chromatography. The absorbance ratio of 784-cm-l to 998-cm-1 bands was found to be linearly related to the molecular weight of the resol.

Order-disorder transition in polymer-diluent systems: elastic constants

“…T,( ) = Tg( ) + A (16) where A is a constant independent of and is greater than zero (see eq 20). The theoretical concept of T8 has been found to be very useful in describing other mechanical properties like yield stress, ay ~T8 -T, quantitatively.16…”

Online monitoring of synthesis and curing of phenol–formaldehyde resol resins by Raman spectroscopy

“…However, none of these methods is well suited for gathering real-time information about the consumption of starting materials or structure of the resins during the resin processes, which could improve the safety and control of the synthesis and result in more uniform resin quality. The use of FTIR spectroscopy for the online process control and study of aqueous resol resins is slightly limited by the broad and overlapping signals and the disturbing effect of water [20] in the spectral data. Until now, liquid state 13 C NMR spectroscopy has been the best method for detailed investigation of the structure of resin solutions, but it is far too slow for online monitoring of the resin syntheses.…”

“…So far, the contribution of Raman spectroscopy to the study of the synthesis of phenolformaldehyde resol resins has been minor, probably due to the difficulties noted above. Chow and Chow [20] followed the changes in intensity of the Raman bands of resol resins during the prepolymer synthesis, and plotted the changes as a function of molar mass of the resin. In addition, Raman spectroscopy has been used in carbonization and graphitization studies of resol resins [21,22].…”