Characterization of the porous structure of polymeric packings for HPLC

Abstract

Using inverse exclusion chromatography, the porous structure of four polymeric stationary phases has been investigated. Three of the copolymers were characterized by a high degree of crosslinking because they were synthesized from I',,vo tetrafunctional monomers. The fourth copolymerwas obtained from styrene (bifunctional monomer) and divinylbenzene (tetrafunctional monomer) and has a significantly smaller degree of crosshnking.To determine the pore size distribution of the copolymers, toluene, alkylphenones, phthalates, and polyslyrene standards were used as probes. Additionally changes of the volume of the copolymers when changing from water to tetrahydrofuran were determined. The results show that more stable porous structures were obtained from tetrafunctional monomers. All polymeric stationary phases have micropores in their internal structure but their contributions are different.

Synthesis of a new tetrafunctional monomer, 1,4‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)phenol, and its copolymerization

“…7 In other approaches, monomers possessing polar functional groups are used in their synthesis. [8][9][10] An important group of such monomers is formed by methacrylate compounds which can possess carboxyl, ester, hydroxyl, etc. functional groups in their structures.…”

Use of a new methacrylic monomer, 4,4′‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzophenone, in the synthesis of porous microspheres

“…According to Nevejans and Verzele,15 the term microporosity defines pores with a diameter smaller than 20 Å. In the studies presented here, the differences between the retention volumes of toluene with a molecular diameter of 9 Å and the molecule of dinonyl phthalate (molecular diameter = 22 Å) indicate the contribution of micropores to the internal structure of the copolymer 1, 15…”

“…The most popular are macroporous copolymers of styrene crosslinked with divinylbenzene (ST–DVB). This modern column packing is characterized by good mechanical stability as a result of the high percentage of the crosslinking agent [divinylbenzene (DVB)], up to 90% 1. Another approach is associated with chemical modification leading to additional crosslinking of the final product 2, 3.…”

Preparation and characterization of porous crosslinked microspheres of new aromatic methacrylates

“…Exclusion chromatography experiments were carried out in THF using as pore-size probes, toluene, alkylphenones, phthalates and polystyrene standards with molecular weights ranging from 580 to 275,000 [25,26].…”