A new rapid method for measuring the surface area of poly(vinyl chloride)

Abstract A gas chromatographic technique has been developed for rapid determination of the specific surface area Sg of PVC resin powders. The basis for this method is the observation that a suitable hydrocarbon vapor, such as n-octane, is almost instantaneously adsorbed onto PVC surfaces at room temperature, while its absorption into the polymer is negligible for several hours. The technique involves the injection of a known amount of n-octane vapor into a vial containing the PVC resin sample, followed by GC analysis for the n-octane remaining in the vapor space. A straightforward material balance calculation then yields the amount of n-octane adsorbed, which can be related to Sg. A procedure involving injections of a fixed dose of n-octane has been calibrated against surface areas determined by the classical BET N2 adsorption method for PVC samples having Sg from 0.3 to 16 m2/g. Alternatively, BET calculations may be applied to n-octane adsorption isotherms determined from varied vapor doses; this method...