%0 journal article
%@ 1381-5148
%A Diez, B., Cuadrado, P., Marcos-Fernandez, M., de la Campa, J.G., Tena, A., Pradanos, P., Palacio, L., Lee, Y.M., Alvarez, C., Lotano, A.E., Hernandez, A.

%D 2018
%J Reactive and Functional Polymers

%P 38-47 
%R doi:10.1016/j.reactfunctpolym.2018.03.013
%T Thermally rearranged polybenzoxazoles made from poly(ortho-hydroxyamide)s. Characterization and evaluation as gas separation membranes
%U https://doi.org/10.1016/j.reactfunctpolym.2018.03.013
 
%X Two series of aromatic poly(ortho-hydroxyamide)s (poly(o-hydroxyamide)s, HPAs) were prepared by reaction of two diamines, 2,2-bis(3-amino-4-hydroxyphenyl) propane (APA) and 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (APAF), with four aromatic diacid chlorides; terephthaloyl dichloride (TPC), isophthaloyl dichloride (IPC), 2,2-bis[4-chlorocarbonylphenyl)hexafluoropropane (6FC) and 4,4′-sulfonyldibenzoyl dichloride (DBSC). Amorphous HPAs with high molecular weights (inherent viscosities higher than 0.5 dL/g) and relatively high glass transition temperatures (220–280 °C) were obtained. Dense membranes of HPAs were able to undergo a thermal rearrangement (TR) process to polybenzoxazoles (β-TR-PBOs) heating at moderate temperatures (between 250 and 375 °C), and their complete conversion was reached at a temperature below 375 °C, depending on the o-hydroxy diamine moiety, APA and APAF. The β-TR-PBOs films derived from APAF showed a higher thermal stability and higher Tg than those from APA. Gas separation properties of TR-PBOs membranes were superior to those of their poly(o-hydroxyamide) precursors, particularly for the following gas pairs: O2/N2, CO2/CH4, He/CH4 and He/CO2.