Thermal induced structural changes of polyhydroxyamide by two-dimensional (2D) infrared correlation study

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Two-dimensional (2D) correlation analysis of <I>in situ</I> FTIR spectra was used to probe the thermally induced structural changes in a poly(hydroxyamide) (PHA) precursor prepared from the reaction of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (Bis-AP-AF) with terephthaloyl chloride. Large spectral changes in the <I>in situ</I> FTIR spectra of the PHA precursor film were observed in the range of 200–300 °C. The thermal cyclodehydration reaction of the PHA precursor film strongly affects the spectral changes corresponding to the amide group and the adjacent phenyl ring in the Bis-AP-AF unit. The thermal cyclodehydration reaction of the PHA precursor film in the range of 240–300 °C induced the spectral changes in amide linkage before the formation of the benzoxazole ring.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Investigation of the structural evolution of a PHA precursor to PBO using <I>in situ</I> FTIR spectroscopy. </LI> <LI> 2Dcorrelation analysis of structural changes in the PHA precursor with increasing temperature. </LI> <LI> Thermal cyclization of PHA. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>