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Gradient polymer elution chromatography of methacrylate Telomers on monolithic capillary columns prepared by nitroxide-mediated polymerization
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Linear methacrylate telomers prepared by isopropylxanthic disulfide photoiniferted polymerization of 2-hydroxyethyl methacrylate, methyl methacrylate, and ethyl methacrylate have been separated from their precursor monomers using gradient polymer elution chromatography (GPEC) on a monolithic capillary column. The capillary monoliths were prepared by thermally initiated radical polymerization of styrene and divinylbenzene controlled by 1-carboxy-PROXYL stable free radicals, and characterized by nitrogen adsorption and mercury intrusion porosimetry. The separations in GPEC mode were performed using a mobile phase gradient from water to methanol, where water is the non-solvent and methanol the good solvent with respect to the telomers. Successful separation of telomers from their monomer was achieved for all tested telomers. In addition, it was observed that the retention times of the intact telomers were different from those of telechelic oligomers produced by hydrolysing the isopropylxanthic terminals. The current set-up is therefore promising both for monitoring of the progress of photoiniferted polymerizations and to monitor the hydrolysis of resulting polymerized oligomers into thiol-terminated telechelics.

Keyword [en]
Gradient polymer elution chromatography, telechelics, living polymerization, monoliths, separation of polymers
National Category
Analytical Chemistry Polymer Chemistry
Research subject
Analytical Chemistry
Identifiers
URN: urn:nbn:se:umu:diva-30309OAI: oai:DiVA.org:umu-30309DiVA: diva2:281512
Available from: 2009-12-16 Created: 2009-12-16 Last updated: 2017-05-18Bibliographically approved
In thesis
1. Porous polymeric materials for chromatography: Synthesis, functionalization and characterization
Open this publication in new window or tab >>Porous polymeric materials for chromatography: Synthesis, functionalization and characterization
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Background: Separation science is heavily reliant on materials to fulfill ever more complicated demands raised by other areas of science, notably the rapidly expanding molecular biosciences and environmental monitoring. The key to successful separations lies in a combination of physical properties and surface chemistry of stationary phases used in liquid chromatographic separation, and this thesis address both aspects of novel separation materials.

Methods: The thesis accounts for several approaches taken during the course of my graduate studies, and the main approaches have been i) to test a wild-grown variety of published methods for surface treatment of fused silica capillaries, to ascertain firm attachment of polymeric monoliths to the wall of microcolumns prepared in silica conduits; ii) developing a novel porogen scheme for organic monoliths including polymeric porogens and macromonomers; iii) evaluating a mesoporous styrenic monolith for characterization of telomers intended for use in surface modification schemes and; iv) to critically assess the validity of a common shortcut used for estimating the porosity of monoliths prepared in microconduits; and finally v) employing plasma chemistry for activating and subsequently modifying the surface of rigid, monodisperse particles prepared from divinylbenzene.

Results: The efforts accounted for above have resulted in i) better knowledge of the etching and functionalization parameters that determine attachment of organic monoliths prepared by radical polymerization to the surface of silica; ii) polar methacrylic monoliths with a designed macroporosity that approaches the desired "connected rod" macropore morphology; iii) estab¬lishing the usefulness of monoliths prepared via nitroxide mediated polymerization in gradient polymer elution chromatography; iv) proving that scanning electron microscopy images are of limited value for assessing the macroporous properties of organic monoliths, and that pore measurements on externally polymerized monolith cocktails do not represent the porous properties of the same cocktail polymerized in narrow confinements; and v) showing that plasma bromination can be used as an activation step for rigid divinylbenzene particles to act as grafting handles for epoxy-containing telomers, that can be attached in a sufficiently dense layer and converted into carboxylate cation exchange layer that allows protein separations in fully aqueous eluents.

Place, publisher, year, edition, pages
Umeå: Kemiska Institutionen, Umeå universitet, 2009. 45 p.
Keyword
porous polymer monolith, pore size distribution, nitrogen sorptiometry, mercury intrusion porosimetry, scanning and transmission electron microscopy, plasma functionalization
National Category
Analytical Chemistry Analytical Chemistry Polymer Chemistry
Research subject
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-30314 (URN)978-91-7264-934-7 (ISBN)
Public defence
2010-01-15, KBC-Huset, KB3A9, Umeå Universitet, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2009-12-18 Created: 2009-12-16 Last updated: 2017-05-18Bibliographically approved
2. Synthesis and modifications of materials for separation science
Open this publication in new window or tab >>Synthesis and modifications of materials for separation science
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis deals with the preparation of materials for use in separation science and their surface modification by grafting. The overall aim is the preparation of diverse materials by combination of a set of developed tools.

Included in the thesis is the synthesis of monolithic media using non-traditional crosslinkers, the characterization of their porous properties and initial testing in reversed-phase chromatographic separation of proteins. The preparation of a library of short polymer chains, telomers, with varied functionality and their characterization is reported. Included in the characterization is the gradient polymer elution chromatography of selected telomers on a monolithic column in capillary format. The technique shows promise as a tool for monitoring of polymerization processes and for the separation of telomers with similar size but different functionalities or characteristics.

Finally, the combination of polymeric support materials and the prepared telomer library is used in surface modification. Surface modification is performed onto activated surfaces via a “grafting to” approach. One example is shown, the surface modification of epoxy-modified divinylbenzene particles by attachment of telomer chains introducing ion-exchange functionality. The material is tested for the separation of proteins, in ion-exchange chromatography mode.

Place, publisher, year, edition, pages
Umeå: Kemi, 2008. 43 p.
Keyword
material synthesis, monolith, surface modification, telomer, “grafting to”, gradient polymer elution, chromatography
National Category
Other Basic Medicine
Identifiers
urn:nbn:se:umu:diva-1572 (URN)978-91-7264-528-8 (ISBN)
Public defence
2008-03-28, N360, Naturvetarhuset, Umeå Universitet, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2008-03-07 Created: 2008-03-07 Last updated: 2017-05-18Bibliographically approved

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