Four different phosphoric amides, p-phenyl-, phosphonic diamide (2-NH2-PH), phenylphosphonic-, bis(N-butylamide) (2-BU-PH), phenylphosphorobis(N- butylamide) (2-BU-PHO) and phenylphosphonicbis(N-benzylamide) (2-BZ-PH), have been successfully synthe- sized by low temperature condensation and characterized, by FT-IR, H-1 NMR and P-31 NMR. These phosphoric, amides have been used to cure commercially available unmodified, liquid epoxy resins. The curing behaviors and thermal stability of the cured films have been studied. Comparing the curing temperatures (initial (T-i), peak (T-p), and final (T-f)) and the degree of curing, it has been,, observed that using the curing agent containing bulks, groups i.e., more sterically hindered structure, results in higher curing temperatures but a lower degree of curing, When comparing 2-BU-PHO, which contains a phenoxy group, with 2-BU-PH containing a phenyl group in the, back bone, it is interesting to note that the phosphorus content in 2-BU-PHO is lower (4.81) than that of 2-BU-PH (4.93), but the residual weight percent at 800 degreesC (R-800) and also the temperature needed to obtain 10 weight loss (T-0.1) is significantly higher for 2-BU-PHO cured epoxies. Also the results from 2-BZ-PH, which unlike 2-BU-PH contains aromatic benzyl groups, indicate, that the aromaticity of the curing agent does not affect the thermal stability of the cured polymer film. References: 26
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