Glass transition of adsorbed stereoregular PPMA by inverse gas chromatography at infinite dilution

In this paper, we used inverse gas chromatography (IGC) at infinite dilution that proved to be a powerful technique to determine glass transition and other transitions of PMMA adsorbed on a-alumina. We highlighted the glass transition temperature of the system PMMA/alpha-Al2O3 with defined polymer tacticity at various covered surface fractions. Thus, the Tg of the adsorbed isotactic PMMA increases strongly as compared to the bulk value. The study of the physical chemical properties of PMMA/alpha-alumina revealed an important difference in the acidic and basic behaviour, in Lewis terms, of aluminium oxide covered by various concentrations of PMMA. It appears that there is a stabilisation of the physical chemical properties of PMMA/alpha-Al2O3 for a surface coverage above 50 %. This study also highlighted an important effect of the tacticity of the polymer on the acid-base character of the system PMMA/Al2O3.