Analysis of the radiative properties of insulating and conducting granular polymers and of their mixtures

The radiative and electrical properties of an inhomogeneous material made of polyvinyl chloride (PVC, insulating polymer) in granular form on which a polypyrrole (PPy, conducting polymer) coating has been deposited by polymerization of pyrrole are described in this paper. The properties of the obtained encapsulated powders (PVC–PPy) are directly related to the nature of the substrate (composition, granulometry and surface state) and to the preparation conditions (concentration of reactants, temperature and duration of the polymerization). In the following, we report the spectral study of powders PVC, PVC–PPy and of their mixtures in the UV, visible, near (NIR)- and mid-infrared (MIR) wavelength ranges. In other respects, the study of the electrical conduction of the materials allows us, on one hand, to demonstrate the influence of the conditions of polymerization on the electrical behavior, and on the other hand, to show off the electrical threshold of the insulator–conductor mixtures.