Characterization of Substituted Phenol-formaldehyde Resins Using Solid-state Carbon-13 NMR

Crosslinked substituted phenol-formaldehyde resins were synthesized from cashew nut shell liquid 3-n-pentadecylphenol and phenol with formaldehyde. the resulting resins were crosslinked and investigated using carbon-13 NMR in the solid state using cross-polarization, magic angle spinning, and dipolar decoupling. Comparisons were made between the spectra of pure phenol-formaldehyde and modified phenol-formaldehyde resins and it was shown possible to distinguish between the resins. It was also show that the proton-dephased spectrum gave better spectral resolution for the substituted compounds. in addition, the solids carbon-13 technique verified that the degradation of the substituted phenolic resins occurs first with the degradation of the side chain in agreement with suggestions from earlier work