| Phenol-formaldehyde (PF) resol resins, formed from formaldehyde and phenol, are used mainly in applications related to the wood industry, thermal insulation, and molding. Prior studies in our laboratories have studied methylolphenolic model compounds. Ammonia catalyzed production of resol phenol formaldehyde resins produces appreciable amounts of hydroxybenzylamine compounds. Attempts to produce low density carbon cloth phenolic for the NASA shuttle program provide additional incentive to study amine formation. Thus, some model hydroxybenzylamine compounds, including 2-, and 4-hydroxybenzylamines, 2,2'-, and 4,4'-dihydroxydibenzylamines, 2,2',2 ''-, 4,4',4'' -, 2,2',4''-, and 2,4',4''-trihydroxytribenzylamines and benzoxazine were prepared for NMR study.; The primary amines were prepared by two ways. One was from their corresponded hydroxybenzylalcohols, the other was from the reduction of cyanophenols by LiAlH4. The dihydroxydibenzylamines were synthesized from the hydrogenation of cyanophenols using 5% Rh/C. A general synthetic method was developed for the synthesis of trihydroxytribenzylamines. The reaction of the secondary amines with acid chlorides, followed by the LiAlH4 reduction formed the tertiary amines. Benzoxazine was obtained directly from the reaction of phenol with hexamethylenetetramine. 1H and 13C liquid NMR spectra were obtained on the hydroxybenzylamine model compounds in acetone-d6 with 0.03% TMS as internal standard. The C-13 chemical shifts of the methylene carbons of these compounds, including some benzylamines, were characterized. These compounds can be used for qualitative identification by comparison of their spectra with those of the phenolic resins, but also can be good internal standards for further quantitative analysis.; Solid-state CP/MAS 13C NMR was carried out to analyze the phenolic resins in NASA rocket motors, since the final cured resol resin is insoluble and hard. A total number of sixteen samples were analyzed. The NMR data for these samples were obtained, and the precision of the measurements were calculated. A chemical structural model of a cured phenolic resin using a formaldehyde/phenol ratio (F/P) of 1.30 has been developed. This study shows that the solid-state NMR is a powerful tool for phenolic resin analysis.; In this dissertation, the synthesis of the hydroxybenzylamines was discussed. Also, the solid-state NMR methodology for the solid phenolic resins was discussed. |
