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 ha ve a wide variety of applications. Resins of this type are used in the aerospace industry to produce rocket motor components with strength a nd rigidity. While methods currently exist (e.g., DMA, DEA, calorimetr y) for the examination of phenolic-based systems during the curing pro cess, none are available to directly measure the functionality and che mical degree of resin advancement during this process. Solution and so lid-state C-13 NMR spectroscopy can be implemented to examine the func tional group content of the resin. Reactant and product moieties are s pectrally resolved in both techniques and can be monitored during resi n 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 a s 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 functio nal group basis.