INVERSE GAS CHROMATOGRAPHIC STUDY OF RUBBERS

ETHYLENE PROPYLENE RUBBER (EPR) AND ACRYLONITRILE BUTADIENE RUBBER (NBR)

Abstract

The thermodynamic interactions of rubbers (EPR and NBR) with various solvents (probes) were investigated by inverse gas chromatography (IGC) over a wide range of temperature from 60°C to 200°C.
Rubbers were coated on the Support (Chromosorb WAW DMCS (60_??_80 mesh)) as a thin layer film with various concentrations. The Support was carefully packed in the stainless steel column (2.2mm inner diameter×2000mm length).
Retention diagrams (R.D.) of rubber/solvent system were obtained by using the specific volumes (V⁰_g) obtained at 1/w→0 on the lnV_g vs. 1/w plopts. The R. Ds of rubbers showed linear lines in the whole temperature range. Values of the rubber/solvent interaction parameters (χ₁₂) were calculated from the V⁰_gs. The χ₁₂, at 60, 100, and 180°C for EPR with n-C₆H₁₂ were 0.22, 0.15, and -0.22, and for NBR, 1.31, 0.84, and 0.65, respectively. It should be understood that the EPR is more soluble in n-C₆H₁₂ than NBR. The χ₁₂ of other alkane such as n-C₅H₁₂ and n-C₁₀H₂₂ for NBR, were also larger than those for EPR.
The partial molar heat of sorption (_??_H^s₁) of alkane for EPR was larger than for NBR. These data indicate that EPR could adsorb alkane more strongly than NBR.