Effect of the Tacticity of PMMA Adsorbed on Alumina and Silica on the Specific Entropy Change of Polymer by Inverse GC

Abstract

Inverse gas chromatography (IGC) at infinite dilution is a powerful technique to characterize the superficial and interfacial properties of solid substrates as oxides, polymers or polymers adsorbed on oxides. It can also be used to determine the physicochemical properties and the transition phenomena of polymers. In this paper, IGC was used to determine the changes, as a function of temperature, of the specific free enthalpy DG a SP and deduce the specific entropy DS a SP of poly (methyl methacrylate) (PMMA) adsorbed on alumina or on silica for different tacticities of PMMA. The study of the surface properties of PMMA/SiO 2 and PMMA/Al 2 O 3 , revealed an important difference in the physicochemical behaviour of oxides covered by various concentrations of PMMA. This study also highlighted an important effect of the tacticity of the polymer on the specific entropy of PMMA adsorbed on oxides.

Determination of Lewis Acid Base Properties of Poly(α-n-alkyl) Methacrylates Adsorbed on Silica by Inverse GC

“…Godard, Saiter et al [52][53][54] studied the enthalpy relaxation and the transition phenomena in poly (a-n-alkyl) methacrylates (denoted Cn for the alkyl group C n H 2n?1 in the lateral chain) and the effect of the length of lateral chain on the thermal properties of polymers using DSC technique. Their results were recently confirmed by Hamieh et al [55] using IGC technique at infinite dilution.…”

Surface modification of high-performance polymeric fibers by an oxygen plasma. A comparative study of poly(p-phenylene terephthalamide) and poly(p-phenylene benzobisoxazole)

“…On the other hand, if polar probes are injected into the column instead of n-alkanes, the adsorption of the adsorbate molecules on the stationary phase involves not only dispersive but also specific interactions [32][33][34][35]. Thus, -G 0 a is assumed to be the sum of two independent contributions accounting for both types of molecular interaction:…”

Synthesis by ATRP of Polystyrene-b-Poly(4-vinylpyridine) and Characterization by Inverse Gas Chromatography

“…Several methods were employed to determine first, the specific interactions exchanged between polar molecules and a solid surface as polymers or oxides and second to obtain the acid-base interactions [64][65][66][67][68][69]. Hamieh and al studied the physicochemical properties of many oxides [70][71][72][73][74][75][76][77][78][79][80][81][82] and polymers in bulk phase or when adsorbed on oxides [83][84][85][86][87][88][89][90][91][92][93][94][95] by modeling the various models used in inverse gas chromatography and by applying Papirer method [64][65][66].…”

“…Finally, the GTA spectrum of the copolymer PS-P4VP is a composition of two previous spectra of the two homopolymers and has a first inflection point at 160 0 C corresponding to the glass transition of the P4VP block and a sharp drop in weight due to the degradation of the copolymer to 400 The obtained value of ΔH SP is used to determine the values of K A and K D (in our case this equation is treated using the classical model and the model of Hamieh [68][69]. Mamieh model was used on many oxides and polymers and gave interesting results on the acid base properties of solids [72, 74-76, 79-80, 85, 89, 91, 93].…”

“…With NA and ND the electron acceptor and donor numbers, respectively. While Hamieh's model [69] corrected the relationship (11) and proposed a new relationship by adding a third parameter K reflecting the amphoteric character of the oxide or polymer according to:…”