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Porous Space-filling Monolithic Polyvinylidene Difluoride (PVDF) Materials by Thermally Induced Phase Separation
Umeå University, Faculty of Science and Technology, Department of Chemistry. (Research Group for Reactive Polymers in Analytical Chemistry)
Umeå University, Faculty of Science and Technology, Department of Chemistry. (Research Group for Reactive Polymers in Analytical Chemistry)
(English)In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291Article in journal (Refereed) Submitted
Abstract [en]

Thermally induced phase separation was assessed as a means of producing space-filling monoliths from PVDF of three dif­ferent molecular weights in twenty-two different solvents spanning a wide polarity range. Monolithic materials were produced in six out of these solvents; n-butyl butyrate, 1,4-dimethoxy­benzene, cyclohexanone, 2,5-hexanedione, dimethyl succinate, and e-caprolact­one. These monoliths had specific surface areas up to 35 m2/g, with the majority of the measured sur­face area attributable to pores in the mesoporous region from 5-20 nm, depending on solvent. Scanning elec­tron microscopy images re­vealed radically different structures at the macropore level. In three of the samples essentially monodis­perse particles in the 4-5 µm diameter range were found and verified to be of the same chemical compo­sition as the monolithic part of the precipitate. These particles appeared for PVDF of different mole­cular weights and seem to have phase separated by a mechanism dif­fering from the bulk monolith, which could hint at a novel way to prepare monodisperse PVDF particles.

National Category
Chemical Sciences
Research subject
Analytical Chemistry
URN: urn:nbn:se:umu:diva-89308OAI: diva2:719779
Swedish Research Council, 2012-4000
Available from: 2014-05-27 Created: 2014-05-27 Last updated: 2014-08-07Bibliographically approved
In thesis
1. Porous Polymeric Monoliths by Less Common Pathways: Preparation and Characterization
Open this publication in new window or tab >>Porous Polymeric Monoliths by Less Common Pathways: Preparation and Characterization
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis focuses on my endeavors to prepare new porous polymeric monoliths that are viable to use as supports in flow-through processes. Polymer monoliths of various porous properties and different chemical properties have been prepared utilizing the thermally induced phase separation (TIPS) phenomenon and step-growth polymerization reactions. The aim has been to find appropriate synthesis routes to produce separation supports with fully controlled chemical, physical and surface properties. This thesis includes preparation of porous monolithic materials from several non-cross-linked commodity polymers and engineering plastics by dissolution/precipitation process (i.e. TIPS). Elevated temperatures, above the upper critical solution temperature (UCST), were used to dissolve the polymers in appropriate solvents that only dissolve the polymers above this critical temperature. After dissolution, the homogeneous and clear polymer-solvent solution is thermally quenched by cooling. A porous material, of three dimensional structure, is then obtained as the temperature crosses the UCST. More than 20 organic solvents were tested to find the most compatible one that can dissolve the polymer above the UCST and precipitate it back when the temperature is lowered. The effect of using a mixture of two solvents or additives (co-porogenic polymer or surfactant) in the polymer dissolution/precipitation process have been studied more in depth for poly(vinylidine difluoride) (PVDF) polymers of two different molecular weight grades. Monolithic materials showing different pore characteristics could be obtained by varying the composition of the PVDF-solvent mixture during the dissolute­ion/precipitation process. Step-growth polymerization (often called polycondensat­ion reaction) combined with sol-gel process with the aid of porogenic polymer and block copolymer surfactant have also been used as a new route of synthesis for production of porous melamine-formaldehyde (MF) monoliths. In general, the meso- and macro-porous support materials, for which the synthesis/preparation is discussed in this thesis, are useful to a wide variety of applications in separation science and heterogeneous reactions (catalysis).

Place, publisher, year, edition, pages
Umeå: Umeå university, 2014. 63 p.
Monolith, commodity polymer, thermally induced phase separation, dissolution-precipitation, polymer solvents, porogenic polymer, step-growth polymerization, separation science, melamine-formaldehyde
National Category
Analytical Chemistry Polymer Chemistry Materials Chemistry
urn:nbn:se:umu:diva-89322 (URN)978-91-7601-088-4 (ISBN)
Public defence
2014-06-13, KB3B1, KBC-huset, Umeå universitet, Umeå, 13:00 (English)
Available from: 2014-05-28 Created: 2014-05-27 Last updated: 2014-05-28Bibliographically approved

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