Abstract
The emissivity of polymers shows a remarkable change according to the variation of the repeating units. Since it is impossible to measure the monochromatic emissive power of polymers, the emissive phenomenon is investigated in terms of the infrared spectra of atomic vibrations as well as the distribution of blackbody emissive power.
The atomic vibrations contributing to polymer emission are assigned from the infrared absorption spectra. The atomic vibrations around the wave length λmax yielding the maximum emissive power for blackbody emission contribute very effectively to the emissivity of polymers. On the other hand, such vibrations as stretchings of X-H, C≡X and C=X in short wave lengths as well as torsional, rotational and lattice vibration in long wave lengths are rather ineffective.
In general, emissivity is small if the molecules are composed of only C and H atoms and further their symmetry is excellent, whereas if they are composed of various different atoms or they have hydrogen bonding, their emissivity becomes large. Emissivity approaches to unity with the increase in the volume of polymers (i. e. with the increase in thickness of polymer films).
