STRUCTURE OF PYROLYZED POLYVINYLIDENE CHLORIDE

Abstract

Systematic infrared analyses, using the standard KBr pellet technique, of samples ranging from the pure polymer (Saran) to the fully carbonized charcoal have been examined in an attempt to clarify the structural changes and mechanism of decomposition of the polymer on pyrolysis. A complementary technique has been investigated for obtaining homogeneous samples of the carbon and of the partially pyrolyzed polymer which will transmit infrared radiation without the use of any halide dispersal medium. The significance, possible applications, and limitations of these spectral studies are discussed. Pore volumes have been examined by means of a modified helium displacement densitometer and also through the adsorption of argon in a McBain–Bakr balance. Porosity measurements based on the adsorption of argon at its saturation vapor pressure are more satisfactory and they contribute towards a better understanding of the microstructure of Saran charcoal and of its partially carbonized antecedents. The influence of pelletizing pressure has been found to play an important role in the determination of pore volumes.