Investigation of the surface structure of polymers by chromatographic methods: II. Macroporous poly(2-hydroxyethyl methacrylate-co-ethylenedimethacrylates)

Abstract

Macroporous poly(2-hydroxyethyl methacrylate-co-ethylenedimethacrylates) are suitable sorbents for gas chromatography. Their polarity, as described by Kováts' indices, is influenced by the ratio of 2-hydroxyethyl methacrylate to ethylenedimethacrylate, and by the ratio of cyclohexanol to dodecanol used in the polymerization. Interactions of these copolymers with low-molecular-weight compounds under chromatographic conditions are predominantly non-specific. The specific interactions are mainly due to the formation of hydrogen bonds. From the dependence of the logarithm of the specific retention volumes of pentane and ethanol on 1/ T, it may be inferred that, up to the glass transition temperature of the polymer ( T g ), the low-molecular-weight solute is adsorbed on to the surface of the copolymers, while above T g its diffusion into the copolymer sets in (especially with Spheron G10B and G50F); this is confirmed by the sorption isotherms of ethanol and pentane on these copolymers at 150°C.