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Thermally induced dissolution/precipitation: A simple approach for the preparation of Macroporous Monoliths from Linear Aliphatic Polyamides
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.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2009 (English)In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 32, no 15-16, 2619-2628 p.Article in journal (Refereed) Published
Abstract [en]

A versatile way of preparing macroporous monolithic materials from linear aliphatic polyamides is presented. Simply, polyamide pellets were treated in benzyl alcohol (BA) at elevated temperature, causing dissolution by interchain hydrogen bond disruption. Subsequent cooling below the upper critical solution temperature (UCST) resulted in precipitation and partial restoration of the semicrystalline polymer, which is organized into network structures. The final steps were a solvent exchange of BA for methanol, followed by drying to form monolithic entities. A number of polyamides ranging from hydrophilic to hydrophobic were tested and under the experimental conditions, poly(1-aza-2-cycloheptanone (PA6) and (poly-[imino-1,6-hexanediylimino{1,10-dioxo-1,10-decanediyl}] (PA610) yielded entities with macroporous properties that were deemed useful for liquid chromatography. The morphological features and porous properties of the monoliths produced by this dissolution-precipitation procedure were studied by scanning electron microscopy, adsorption/desorption of N2(g) according to the Brunauer-Emmett-Teller (BET) principle, and mercury intrusion porosimetry. Degradation of the polymer backbone was noticeable when the dissolution time was extended and shortening of the polymer chains was confirmed by MALDI-MS, viscosity measurements, X-ray photoelectron spectroscopy (XPS), and potentiometric titration. When the heating was limited to the time it took to dissolve the polymers, mechanically stable monoliths could be obtained. The dissolution/heat treatment time further seemed to be useful for controlling the macroporous morphology.

Place, publisher, year, edition, pages
Wiley InterScience , 2009. Vol. 32, no 15-16, 2619-2628 p.
Keyword [en]
Dissolution, Non-acidic solvent, Nylon, Polyamides, Polymer degradation, Porous monoliths, Precipitation, Upper critical solution temperature (UCST)
National Category
Analytical Chemistry
Research subject
Analytical Chemistry
Identifiers
URN: urn:nbn:se:umu:diva-20888DOI: 10.1002/jssc.200900241OAI: oai:DiVA.org:umu-20888DiVA: diva2:209817
Available from: 2009-03-27 Created: 2009-03-27 Last updated: 2012-08-09Bibliographically approved
In thesis
1. New approaches to preparation of macroporous monoliths for use in liquid chromatography
Open this publication in new window or tab >>New approaches to preparation of macroporous monoliths for use in liquid chromatography
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

High performance liquid chromatography (HPLC) is one of the major techniques in separat-ion sciences. Faster separation and higher efficiency are required to meet ever-growing demands. Despite numerous studies and achievements on improving mass transfer in particulate packings discontinuity seems to be the cornerstone drawback in their development. Macroporous continuous beds or monoliths are therefore a promising alternative to the particle medium. This thesis deals with preparation of new monoliths used as carrier for HPLC. Two different approaches were developed for two polymer systems. One was based on polycondensation of epoxy resins and polyamines which were components of an oil-in-water emulsion. An epoxy resin mixture was dispersed in aqueous polyamine phase with the aid of a surfactant. The other involved a traverse of a ready-made polymer solution around its upper critical solution temperature (UCST). In other words, linear polyamides, non-covalently crosslinked polymers, dissolved in a solvent at temperature higher than their UCST followed by slow cooling to below the critical temperature to precipitate the polymers. Partly re-established hydrogen bonds resulted in the formation of crystallites that interconnected into a network structure. Factors controlling morphology and porosity of final products were investigated. The study also deals with surface modifying for chromatographic applications. Functionalization pathways attempted in the thesis were quaterization of inherent amine of the epoxy-based monoliths and grafting tentacle ion groups via glycidyl methacrylate by atom transfer radical polymerization (ATRP) for ion exchange chromatography (IEC).

Place, publisher, year, edition, pages
Umeå: Umeå University, Department of Chemistry, 2009. 53 p.
Keyword
monolith, polycondensation, dissolution-precipitation, epoxy-amine, poly-amide, nylon, emulsion polymerization, characterization, protein separation, liquid chromatography
National Category
Analytical Chemistry
Research subject
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-20890 (URN)978-91-7264-772-5 (ISBN)
Distributor:
Kemiska institutionen, 90187, Umeå
Public defence
2009-04-17, KB3A9, Umeå University, Chemistry, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2009-03-30 Created: 2009-03-27 Last updated: 2014-03-10Bibliographically approved

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Nordborg, AnnaShchukarev, AndreyIrgum, Knut

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