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1.
Highly porous open-cellular monoliths from 2-hydroxyethyl methacrylate based high internal phase emulsions (HIPEs) : preparation and void size tuning
Sebastijan Kovačič, Dejan Štefanec, Peter Krajnc, 2007, izvirni znanstveni članek

Opis: Preparation of highly porous (up to 80% pore volume) open-cellular monolithic cross-linked polymers from 2-hydroxyethyl methacrylate is reported. Oil-in-water and water-in-oil high internal phase emulsions are applied as porosity templates, resulting in an interconnected porous structure with void diameters between 550 nm and 18 m. Significantly larger voids were obtained inthe case of oil-in-water emulsions (between 5 and 18 m) as opposed to water in oil emulsions (approx 600 nm). Controlled coarsening exploiting limited kinetical stability of emulsions was used to obtain monoliths with larger voids, diameters being enlarged 3-fold.
Ključne besede: organic chemistry, polymerization, monolithic polymers, HIPE, emulsions, porous materials, methacrylates
Objavljeno: 31.05.2012; Ogledov: 1355; Prenosov: 45
URL Povezava na celotno besedilo

2.
Aryl acrylate based high-internal-phase emulsions as precursors for reactive monolithic polymer supports
Peter Krajnc, Dejan Štefanec, Jane F. Brown, Neil R. Cameron, 2005, izvirni znanstveni članek

Opis: Water-in-oil high-internal-phase emulsions (HIPEs), containing 4-nitrophenyl acrylate and 2,4,6-trichlorophenyl acrylate as reactive monomers, were prepared and polymerized, and highly porous monolithic materials resulted. The novel materials were studied by combustion analysis, Fourier transform infrared spectroscopy scanning electron microscopy, mercury porosimetry, and N2 adsorption/desorption analysis. With both esters, cellular macroporous monolithic polymers were obtained: the use of 4-nitrophenyl acrylate resulted in a cellular material with void diameters between 3 and 7 m and approximately3-m interconnects, whereas the use of 2,4,6-trichlorophenyl acrylate yielded a foam with void diameters between 2 and 5 m, most interconnects being around 1 m. The resulting monoliths proved to be very reactive toward nucleophiles, and possibilities of functionalizing the novel polymer supports were demonstrated via reactions with amines bearing additional functional groups and via the synthesis of an acid chloride derivative. Tris(hydroxymethyl)aminomethane and tris(2-aminoethyl)amine derivatives were obtained. The hydrolysis of 4-nitrophenylacrylate removed thenitrophenyl group, yielding a monolithic acrylic acid polymer. Furthermore,functionalization to immobilized acid chloride was performed very efficiently, with more than 95% of the acid groups reacting. The measurement of the nitrogen content in 4-nitrophenyl acrylate poly(HIPE)s after various times of hydrolysis showed the influence of the total pore volume of the monolithic polymers on the velocity of the reaction, which was faster with themore porous polymer.
Ključne besede: organic chemistry, macroporous polymers, monolithic polymer supports, emulsion polymerisation, foams, functionalization of polymers, high-internal-phase emulsions
Objavljeno: 01.06.2012; Ogledov: 1205; Prenosov: 61
URL Povezava na celotno besedilo

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