Poly hexamethylene-a-truxillamide

Polyamides derived from the condensation of cinnamic acid photodimers with aliphatic diamines such as poly(hexamethylene-a-truxillamide) (4.67) are highly photodegradable, photochromic materials. 

This polyamide exhibits a reverse degradation-polymerization reaction [2088]. Under UV irradiation at 224 nm, the polyamide is degraded and characteristic trans-cinnamide absorption is observed. This trans-cinnamide absorption disappears following exposure to light of wavelength 304 nm (Fig. 4.9), and poly(hexamethylene-a-truxillamide) is reformed (Fig. 4.10). The observed reverse reaction can be explained by the following mechanism ... 

Fig. 4.9. Change in the ultraviolet absorption spectrum of poly(hexamethylene-a-truxillamide) during UV irradiation at 224 nm [2088]. (Reproduced with permission from [2088] published by John Wiley Sons, Inc., 1971.)...

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