Comparative study on molecular associations in solid and liquid phases of aqueous solutions. I. Topoenergetic representation of the behaviour of several sulphates

Abstract

The previously obtained results on sulphate‐water interactions both in liquid and solid states in the four measuring systems (high resolution mixing calorimetry, differntial scanning calorimetry, thermomechanical analysis, and dynamic thermal densimetric analysis) are retrieved according to the universal topoenergetic procedure by considering the solute concentration as governing potential. Ontogenic and phylogenic parameters defining the nature, the overall amplitude, the mass of the kinetic entity and the coupling strength of these interactions, allow to establish the composite structure both of pure water and of aqueous solutions. At least two structures exist in these specimens made from the pure water with isolated molecules and polymerized water molecules involving cations which catalyze H‐bond forming in polymeric chains.

Ion‐exchange resins. III. Functionalization–morphology correlations in the synthesis of some macroporous, strong basic anion exchangers and uranium‐sorption properties evaluation

“…38 -40 It has been already demonstrated that the morphological changes, which occur by removing 2EH from the macroporous S-DVB copolymers by azeotropic distillation with water, are reversible, the collapsed network being completely re-expanded in a proper solvent (e.g., toluene), and the real porosity was evidenced after the removal of the good solvent with methanol. 38 Such behavior also has been observed for other systems. 9,11,14,17,21 This shows that the whole pore structure of these copolymers is memorized by the copolymer network, 20,23 and a good flexibility of the internuclear chains, which could be a very useful characteristic in the synthesis of some macroporous SBAEs with a high osmotic resistance.…”

“…III prepared in the presence of 2EH as porogen with D in the range of 0.45-0.55, always led to a decrease of the specific surface area. 38 A very small decrease of the average pore radius was observed after chloromethylation for the starting copolymers, which had pores with r p 's in the range of 10 -20 nm, prepared at a dilution of D ϭ 0.45 and a high increase of the r p after chloromethylation of macroporous copolymers, as much as the porosity was higher. 38 This showed that the morphological changes determined by the chloromethylation reaction depend both on the chloromethylation reagent and on the copolymer structure.…”

“…A very small influence of the DVB content was observed for the same porogen at a dilution of 0.45 (results from ref. 38 included in Fig. 3 for comparison).…”

“…27 So far, the most used chloromethylation agent is monochloromethyl ether (MCME). 24,25,27,38 Considering the stricter rules against carcinogens, there is a trend to use other reagents for the functionalization of S-DVB copolymers with chloromethyl groups. Thus, Warshawsky et al 41 performed the chloromethylation of polysulfones with C 8 H 17 OCH 2 X (X ϭ Cl, Br) in the presence of SnX 4 (X ϭ Cl, Br).…”

Ion‐exchange resins. II. Acrylamide crosslinked copolymers as precursors for some ion exchangers

“…The most commonly used starting copolymers for obtaining ion exchangers with different functionalities and morphologies are still styrene-divinylbenzene (S-DVB) copolymers. [1][2][3][4] Among functional polymers, linear and crosslinked copolymers bearing primary amine groups are of a great interest because of their high reactivity, which allows the incorporation of numerous additional moieties. [5][6][7][8][9] However, ion exchangers with primary amine groups are difficult to obtain by chemical reactions of S-DVB copolymers.…”