Fundamental aspects of adsorption chromatography of polymers and their experimental verification by thin-layer chromatography

Belenky, B.G.; Gankina, E.S.; Tennikov, M.B.; Vilenchik, L.Z.

doi:10.1016/s0021-9673(00)85121-3

Cited by 125 publications

(66 citation statements)

References 8 publications

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“…These techniques are mainly based on the size exclusion chromatography (SEC) using hyphenThe molecular characterization of complex polyated detection, i.e., the combinations of different mer systems such as blends, copolymers, and concentration or mass detectors that can be supfunctional polymers is often attempted using variplemented with the molecular properties measuring devices such as light scattering photometers hyphenations: the chemically different species effects. 4,5 This compensation results in the independence of retention volumes for macromolecumay mutually influence their retention and, on the other hand the chemically or structurally dislar chains of their molar masses. As a result, the complex polymer systems can be separated into tinct species of different molar masses may exhibit the same size in solution and, consequently, groups of their constituents according to either chemical composition or physical structure, prothe same retention volume in SEC.…”

Section: Introductionmentioning

confidence: 99%

Liquid chromatography of macromolecules at the critical adsorption point. II. Role of column packing: Bare silica gel

Berek

Jančo

Meira

1998

J. Polym. Sci. A Polym. Chem.

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Section: Introductionmentioning

confidence: 99%

Liquid chromatography of macromolecules at the critical adsorption point. II. Role of column packing: Bare silica gel

Berek

Jančo

Meira

1998

J. Polym. Sci. A Polym. Chem.

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“…33 LCCC utilizes the compensation of size exclusion and interaction effect of polymer chains with porous packing materials in chromatographic separation. At the critical condition of a linear polymer species, the retention of linear polymers becomes independent of molecular weight 34 while the retention of ring polymers depends on molecular weight and differs from that of linear polymers.…”

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confidence: 99%

Preparation and Characterization of Cyclic Polystyrenes

Cho

Masuoka

Koguchi

et al. 2005

Polym J

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ABSTRACT:Macrocyclic polystyrenes with various molecular weight were prepared by the reaction of linear polystyrene having two end vinyl groups and potassium naphthalenide as a coupling agent. Intermolecular side reactions produced higher molecular weight polycondensates and undesirable chain termination reactions also produced linear precursors in addition to the designed molecules. In order to isolate cyclic polymers from the ring closure reaction mixtures, preparative size exclusion chromatography (SEC) method was employed. The purity of SEC-fractionated cyclic polystyrenes was rigorously examined by liquid chromatography at the critical condition (LCCC) and interaction chromatography (IC). After SEC-fractionation, we obtained large amount of highly pure cyclic polymers, though high molecular weight cyclic polymers contain very small amount of linear precursor (< 5%). The purity and isotope effect on reversed-phase liquid chromatography (RPLC) were also rigorously investigated by preparing a deuterated cyclic polystyrene. [DOI 10.1295/polymj.37.506] KEY WORDS Cyclic Polystyrene / GPC Fractionation / LCCC / Isotope Effect / Cyclic macromolecules are of great interest in the investigation of the influence of cyclization on their solution, melt, and solid-state properties. Various physical properties of cyclic polymers have been predicted not only by theoretical methods 1-4 but also by computer simulation studies, 5-7 while they have also been examined experimentally. [8][9][10][11][12][13][14] Cyclic polymers were usually synthesized by the coupling reaction between living precursor polymers with functional groups on both ends and bifunctional linking agents. For example, polystyrenes 9,15-19 and poly(2-vinylpyridine)s 20,21 have been synthesized by this method. Furthermore, , !-heterobifunctional polymers have been used for the synthesis of cyclic polymers.22-24 However, side reactions produce linear precursor polymers, and intermolecular reactions simultaneously produce dimeric and higher molecular weight linear polycondensates. Therefore, it is very difficult to obtain pure cyclic polymers directly, and fractionation is necessary in order to obtain cyclic polymers with high purity. For the isolation of cyclic polymers from the ring closure reaction mixtures, two major fractionation methods have been employed: fractional precipitation method 9,14,[16][17][18] and preparative size exclusion chromatography (SEC). 25,26 Furthermore, liquid chromatography at the critical condition method (LCCC) has been successfully applied for the characterization of cyclic polymers.27-30 Throughout these experimental studies, however, the direct evidence of cyclic structure was not shown, in addition to the fact that the purity of the cyclic molecules has not been determined quantitatively in most of the works. Only for the low molecular weight cyclic polymers, the detailed cyclic structures were directly confirmed by NMR analysis of linking points, 22,23 pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 31 and matri...

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“…The first theoretical analysis of IPC has been reported twenty years ago by Belenky et al 14 In the context of this theory, the partition coefficients K D (pore diameter D) are subdivide into two parts:…”

Section: Resultsmentioning

confidence: 99%

Direction of Temperature Gradient and Retention Mechanism in Normal-Phase Temperature Gradient Interaction Chromatography for Poly(methyl methacrylate) Fractionation

Matsumoto

Kawai

Teramachi

2007

Polym J

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ABSTRACT:Temperature gradient interaction chromatography (TGIC) is a powerful technique for molecular characterization of polymers, in which the interaction strength is controlled by varying the column temperature. In the present paper, the direction of temperature gradient for normal-phase mode TGIC in poly(methyl methacrylate) (PMMA) fractionation was studied by using System I (column: cyano-modified silica == eluent: 1,4-dioxane/n-hexane) and System II (bare silica == 1,4-dioxane/CH 2 Cl 2 ), respectively. It was found that PMMA samples were separated by positive and negative temperature gradients using the respective systems. The results were also discussed theoretically. 1,2 TGIC separates polymer components in the order of molecular weight with a resolution superior to size exclusion chromatography (SEC). TGIC separation is driven mainly by adsorptive interaction between solutes and stationary phase and the strength of the interaction is controlled by varying the column temperature, to offset the molecular weight dependency of the adsorption strength. During the sample elution, the column temperature is varied continuously by positive (rising) or negative (lowering) temperature gradient. In many studies of TGIC, reversed-phase mode TGIC (RP-TGIC) has been applied to the separation of various polymers. In almost all cases of RP-TGIC, the positive temperature gradient was applied. The exception reported so far was a case where poly(ethylene oxide) (PEO) was fractionated using C18 bonded silica column and a mixture of acetonitrile and water by negative temperature gradient.2-4 On the other hand, the results in the normal-phase mode TGIC (NP-TGIC) reported are not so many. However both temperature gradients were reported in NP-TGIC. That is, polystyrene (PS), 5,6 polyisoprene (PI), 5 PEO 4 and poly(2-vinylpyridine) (P2VP) 7 were separated by the positive temperature gradient, whereas PS samples were separated also by the negative temperature gradient using the respective columns of bare silica and NH 2 -modified silica packing materials and the eluent mixtures of chloroform and n-hexane (nHx) at the respective compositions in our previous work. 6 It was reported that the positive temperature dependencies of the retention were obtained for PS 8 and poly(styrene-co-methyl methacrylate) [P(S-co-MMA)] 9 in common organic eluents and also poly(ethylene glycol) in aqueous eluents.10 If these systems were used for NP-TGIC, the negative temperature gradient should be effective. Then, it is very interesting whether not only low polar polymer PS but also high polar polymer poly(methyl methacrylate) (PMMA) can be separated by both of positive and negative temperature gradients in NP-TGIC. All cases of TGIC separation of PMMA samples reported so far were carried out by RP-mode using positive temperature gradient, as far as we know. However, PMMA samples and block copolymer samples involving PMMA block were separated mainly by NP-mode in the liquid chromatography at the critical condition (LCCC), 11,12 and the above mentio...

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Fundamental aspects of adsorption chromatography of polymers and their experimental verification by thin-layer chromatography

Cited by 125 publications

References 8 publications

Liquid chromatography of macromolecules at the critical adsorption point. II. Role of column packing: Bare silica gel

Liquid chromatography of macromolecules at the critical adsorption point. II. Role of column packing: Bare silica gel

Preparation and Characterization of Cyclic Polystyrenes

Direction of Temperature Gradient and Retention Mechanism in Normal-Phase Temperature Gradient Interaction Chromatography for Poly(methyl methacrylate) Fractionation

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