Structural study on rodlike aromatic polyimides derived by solid-state thermal and chemical imidization of poly(amic n-dodecyl ester)

Structural Study on Aromatic Poly(amic n-alkyl ester)s and Their Derivatives by Solid-State Imidization I. Effect of Alkyl Chains on the Structure Change

“…7. As suggested in PA-12 [10], the dilution of basic pyridine in toluene decreased the reaction rate of PA-n as suggested by comparison of Fig. 7a and 7b, and the reaction progressed further by soaking the film for longer time as found from Fig.…”

“…The expected final material is a mesoporous PPPI, contains well-ordered nanometer-sized cavities like a smart membrane proposed by Tsujita et al [20]. On these presumptions, in the previous paper, morphology of PA-12 before and after solid-state thermal and chemical imidization reactions was investigated [10]. After the reaction, formation of imide ring and removal of 1-dodecanol was confirmed by Fourier transform infrared (FT-IR) spectrum.…”

“…6b. Instead, a sharp reflection indicated by an arrow, which can be assigned as crystalline lattice of PPPI produced by the imidization [10,22], was observed. These results suggest that the layered structure in PA-14 cannot be maintained after the reaction at 250 , and by the removal of tetradecyl alcohol from the sample, the produced polyimide chains segregated with each other to form PPPI crystalline lattice.…”

“…As indicated in the previous paper [10], FT-IR spectrum is useful for evaluation of the progress of stretching mode, respectively, so a degree of progress for imidization reaction, αimide, and a fraction of the remaining alkyl chains, αalkyl, can be evaluated from intensity of these peaks. In these calculations, intensity for the aromatic ring absorption at 1515 cm −1 was used as internal reference.…”

“…In the previous paper [10], chemical imidization reaction of PA-12 with using pyridine as base catalyst was performed. The same imidization procedure was conducted for PA-n, i.e., soaking the film in pure pyridine or pyridine/toluene mixture (1/5 in volume) at 80 .…”