Poly( p benzamide) can be dissolved in DMSO NaH system

giving a homogenious solution of polyanion.After evaporating DMSO and using some solvents for regenerating polyanion into poly( p benzamide)

regenerated films were obtained.By X-ray diffraction

the dried films at room temperature are amorphous.Heat treating at 130℃ for 14h did not influence the structures of the films very much

but after heat treating at 250℃ or 300℃ for 30s

the structures of the films changed from amorphous state into modification 1 or modification 2 of crystal.Comparing with modification 1

modification 2 had reflections at d=0.49nm and d=0.28nm strongly

but the reflection corresponding to the reflection at d=0.31nm ini modification 1 disappeared or could not be observed clearly.