MONOLAYER BEHAVIORS OF POLY(HEXAMETHYLENE ADIPAMIDE) AT THE AIR-WATER-INTERFACE

Monolayer films on the neutral water substrate were obtained by spread ing N-trifluoroacetic anhydride (NTF)-modified nylon 66 or nylon 612 i n chloroform solutions. Alternatively, monolayer films were : obtained by spreading from nylon 66 solutions in the 3:1 mixture of benzene (B ) and phenol (P). The temperatures studied are 10.3 degrees, 14.7 degr ees C, and 19.4 degrees C. The isothermss of surface pressure (pi), an d surface moment (mu) against surface area per residue (A) were determ ined. The pi-A isotherms of the NTF-modified nylon 66/chloroform and t he nylon 66/BP were found to be an expanded type, while that of NTF-mo dified nylon 612/chloroform was of a condensed type. The NTF-modified nylon 66/chloroform solutions could yield well-spread films even at hi gher concentrations than nylon 66/BP solutions. In the mu-A isotherms at 10.3 degrees and 14.7 degrees C, the surface moments are constant a t 143 mD/residue for NTF-modified nylon 66/chloroform, and 340 mD/resi due for nylon 66/BP until the surface area reaches where the pi-A isot herms show a transition point. After the transition point, the surface moments for both systems drop steadily. However, the surface moment a t 19.4 degrees C shows a maximum at the transition point. Possible con figuration of the nylon 66 residue in monolayer is discussed.