Cq. Yang et Jr. Simms, COMPARISON OF PHOTOACOUSTIC, DIFFUSE-REFLECTANCE AND TRANSMISSION INFRARED-SPECTROSCOPY FOR THE STUDY OF CARBON-FIBERS, Fuel, 74(4), 1995, pp. 543-548
Three infrared spectroscopic methods-photoacoustic, diffuse reflectanc
e and transmission-were evaluated for the qualitative analysis of carb
on fibres. Transmission spectra of a potassium bromide (KBr) pellet de
tect the bulk of a carbon fibre, and are subject to interference by wa
ter in the KBr pellet. Extensive dehydration of a KBr pellet at elevat
ed temperatures may cause chemical changes. In contrast, photoacoustic
and diffuse reflectance methods are free of water interference. Both
methods differentiate the near-surface region of a carbon fibre from i
ts bulk, thus providing information about chemical structures in the n
ear-surface. The photoacoustic, diffuse reflectance and transmission i
nfrared spectra of a carbon fibre have similar band frequencies. There
fore diffuse reflectance and photoacoustic methods can be used for rel
iable qualitative analysis of carbon fibres.