STUDY OF THE RADIATIVE PROPERTIES OF POWDERED AND FIBROUS POLYMERS

Radiative properties are wavelength dependent; they characterize the m aterial and the spectrum is its fingerprint. The scattering is control led by the physical aspect of the material and, for example, radiative properties are affected by the surface state of the sample, the parti cle size in case of powders, the aspect ratio (length/diameter) and th e orientation of the fibers in case of fibrous materials. It is import ant to know the radiative properties of materials in order to evaluate the radiative heat transfer. Bandwidths and relative intensities vary with these physical parameters which determine the radiative behavior of the material. The results presented in this paper all refer to ref lectances of natural and synthetic fibrous and powdered polymers. The effect of different parameters such as the composition of the material and its surface state on reflectances is shown via principal componen t analysis.