SOLUTION AND SOLID-STATE NMR ANALYSIS OF PHENOLIC RESIN CURE KINETICS

Phenolic condensate resins, produced from the reaction of phenol with formaldehyde, are important components in the chemical industry and have a wide variety of applications. Resins of this type are used in the aerospace industry to produce rocket motor components with strength and rigidity. While methods currently exist (e.g., DMA, DEA, calorimetry) for the examination of phenolic-based systems during the curing process, none are available to directly measure the functionality and chemical degree of resin advancement during this process. Solution and solid-state C-13 NMR spectroscopy can be implemented to examine the functional group content of the resin. Reactant and product moieties are spectrally resolved in both techniques and can be monitored during resin cure. H-1 wide-line solid-state NMR can be used to measure the rate of sample curing in situ by monitoring the sample T2 relaxation time as a function of sample heating time. Comparison of these results with the C-13 NMR data will establish the degree of resin cure on a functional group basis.