1. Ring opening metathesis polymerisation (ROMP) as a tool for polyhipes with extraordinary mechanical propertiesSebastijan Kovačič, 2013, professional article Abstract: PolyHIPE materials have been prepared by Ring Opening Metathesis Polymerisation (ROMP) of dicyclopentadiene. Two characteristic features for successful stabilization of high internal phase emulsions (HIPEs) were tuned in order to achieve improvements regarding mechanical properties of polyHIPEs.Mechanical properties of the new materials were related to variations of the surfactant concentration and the volume ratio of the internal phase in HIPEs. Values for Youngʼs moduli were about a hundred times higher than in standard polyHIPE materials with the same level of porosity, which represents a major improvement for highly porous cellular polymeric materials. Moreover, fully interconnected macroporous morphology was found forpolyHIPEs, where respective HIPEs were stabilized with only 0.25 v% of surfactant.
Keywords: emulsion templating, ring opening metathesis polymerization, dicyclopentadiene, ROMP, mechanical characteristics, polyHIPEs
Published in DKUM: 21.12.2015; Views: 2518; Downloads: 104
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2. Preparation and characterization of poly(high internal phase emulsion) methacrylate monoliths and their application as separation mediaPeter Krajnc, Nermina Leber, Dejan Štefanec, Sandra Kontrec, Aleš Podgornik, 2005, original scientific article Abstract: Poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) monolithic supports were prepared by radical polymerisation of the continuous phase of water in oil high internal phase emulsions. Morphology of monolithic materialswas studied by scanning electron microscopy and mercury intrusion porosimetry. The ratio of phase volume and the degree of crosslinking influenced the void size and pore size distribution of resulting polymers. Void sizes between 1 and 10 m were observed and average pore sizes around 100nm. Polymers with 60, 75, 80 and 90% pore volume were prepared and even samples with highest pore volume showed good mechanical stability. They were modified to bear weak-anion exchange groups and tested on the separation of standard protein mixture containing myoglobin, conalbumine and trypsin inhibitor. Good separation was obtained in a very short time similar to the separation obtained by commercial methacrylate monoliths. However, higher dispersion was observed. Bovine serum albumin dynamic binding capacity for monolith with 90% porosity was close to 9 mg/ml.
Keywords: organic chemistry, methacrylate monoliths, preparation, emulsion polymerization, high porosity, high mechanical stability, polymer chromatographic supports, monolithic methacrylate supports, protein separation
Published in DKUM: 01.06.2012; Views: 2570; Downloads: 67
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3. Oil-in-water high internal phase emulsions for porous monolithic polymersPeter Krajnc, Dejan Štefanec, 2005, published scientific conference contribution abstract Abstract: Porous monolithic polymers are objects of many studies recently due to their wide applicability. Especially in separation methods use of monoliths is growing. Usually, porous monoliths are prepared by bulk polymerisation with the use of porogenic solvents. An alternative way of preparation is to polymerise the continuous phase of an emulsion. When the volume fraction of the internal phase exceeds 74%, the emulsion is called a HIPE (high internal phase emulsion), and a polymer derived from it, a PolyHIPE. PolyHIPEs of styrene, vinylbenzyl chloride and acrylate chemistry have been prepared from awater in oil emulsion system, where monomers are dissolved in the organic phase. We describe the reversed procedure, an oil in water high internal phaseemulsion, where monomers are water soluble. Porous polymers based on acrylic acid and crosslinked with methylenebisacrylamide were prepared by using a high internal phase emulsion with toluene as the oil phase. The influence of initiator and surfactant on the morphology was studied.
Keywords: organic chemistry, porous monolith polymers, polymer supports, preparation, emulsion polymerization, HIPE
Published in DKUM: 01.06.2012; Views: 3498; Downloads: 91
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