FOURIER-TRANSFORM INFRARED-SPECTROSCOPY INVESTIGATIONS OF POLYBENZIMIDAZOLE POLY(BISPHENOL-A CARBONATE) BLENDS

The results of a Fourier transform infrared spectroscopy (FTi.r.) study of the blend formed by poly(2,2'-m-phenylene)-5,5'-bibenzimidazole (PBI) and poly-[2,2-propane-bis(4-phenyl carbonate)] (PC) are discussed. The spectral features observed in the N-H stretching and carbonyl stretching regions of all the compositions investigated have been interpreted in terms of hydrogen bonding interactions occurring between the N-H groups of PBI and the C = O groups of PC. Qualitative as well as quantitative information about these interactions has derived. The FTi.r. results indicate a high degree of molecular mixing between the two components at all blend compositions. A spectroscopic study as a function of temperature of a single blend composition (50/50 wt%) is also reported. A quantitative analysis of the carbonyl region in the spectra yielded information about the onset temperature of large scale molecular mobility. A strong catalytic effect of PBI on the thermal degradation of PC was observed and is also discussed.