Mechanism of Reënforcement. IV. Adsorption of GR-S by Carbon Black

Abstract

Infrared absorption analysis has been carried out to determine whether the adsorption of GR-S (co-polymer of polystyrene and polybutadiene) on carbon black is specific as to the chemical structure of the polymer. The comparison of the relative intensities of the characteristic absorption bands of the original GR-S with the ratios of the intensities of the same bands for the fraction of rubber remaining after certain fractions were specifically removed by carbon black has shown that the adsorption is not specific as to chemical structure within the limits of accuracy of infrared analysis. The particular chemical groups considered were the phenyl structure (infrared absorption at 13.20 and 14.27 microns) of polystyrene and the 1,2 (10.08 and 10.95 microns) and 1,4 (10.37 microns) addition units of butadiene.

Adsorption of Elastomers on Carbon Black

“…Let Wo be the weight of polymer charged, p the density of the rubber, and Vo the volume of solvent in the charge. If the concentration of the solution at the point of apparent equilibrium is ci (grams per volume of solution), the weight of rubber adsorbed will be ai = Wo -CiVo/(lci/p) (1) In the process of determining c,, wi grams of rubber and Vi ml. of solution have been removed.…”

“…In the determination of the critical loading for coherent carbon gel formation small samples of the masterbatch were immersed in benzene, allowed to swell for 30 minutes, and filtered through No. 1 Whatman filter paper.…”