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001-es BibID:	BIBFORM043092
Első szerző:	Keczánné Üveges Andrea (vegyész)
Cím:	Synthesis of Polymeric Nanoparticles by Cross-Linking Copolymerization / Üveges Andrea, Szalóki Melinda, Hartmann John F., Hegedűs Csaba, Borbély János
Dátum:	2008
ISSN:	0024-9297 1520-5835
Megjegyzések:	Soluble cross-linked nanoparticles were prepared by free radical copolymerization of styrene (ST, M1) and ethylene glycol dimethacrylate (EGDM, M2) monomers in homogeneous solution. Spherical nanoparticles were obtained in the early stage of polymerization, and no gelation occurred up to 66% of yield. The isolated particles are decorated with pendant vinyl groups that are target for further polymerization. The molar feed ratio was ST/EGDM = 5/5, the monomer concentration 0.556 mol/dm3 and the initiator concentration 5 mol %. It was found that as the conversion increased, the ratio of pendant vinyl groups reached a maximum value; however, the size of nanoparticles continued to increase with the reaction time. The molecular weight distributions were monomodal at short reaction times (30 and 60 min), however, at longer reaction times (90, 120, and 180 min) these became multimodal. This was caused by intraparticle reactions (branching and cross-linking) and possibly also by interparticle reactions (coupling). The reactive vinyl groups were detected by nuclear magnetic resonance spectroscopy (NMR). The size of nanoparticles in swollen state was determined by dynamic laser light scattering (DLS) method and in dried form by scanning electron microscopy (SEM). Molecular weight and distributions were measured by gel permeation chromatography (GPC).
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	Macromolecules. - 41 : 4 (2008), p. 1223-1228. -
További szerzők:	Szalóki Melinda (1981-) (vegyész) Hartmann, John F. Hegedűs Csaba (1953-) (fogszakorvos) Borbély János (1950-) (vegyész)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM013452
Első szerző:	Keczánné Üveges Andrea (vegyész)
Cím:	Synthesis of Nanoparticles by Cross-linking Copolymerization / A. Uveges, J.F. Hartmann, J. Borbely
Dátum:	2007
Megjegyzések:	Free radical cross-linking copolymerization of styrene with large amounts of ethylene glycol dimethacrylate (monomer feed: ST/EGDM = 5/5) has been investigated in toluene as a homogeneous solution. The conversion, the ratio of pendant vinyl groups and the size of the nanoparticles in the pregel state were measured at various reaction times until the onset of macrogelation. It was found that the highest possible polymer yields were 65% at 0.556 mol/dm3 monomer concentration and nearly 100% at 0.278 mol/dm3 monomer concentration without gelation. The molecular weight distributions were monomodal at low conversions and multimodal at higher conversions. The multimodal molecular weight distributions were caused by branching reactions and crosslinking within the nanoparticles. The copolymers obtained were soluble in standard organic solvents such as toluene and chloroform. Transmission electron micrographs proved the formation of spherical particles (TEM).
ISBN:	1420061836
Tárgyszavak:	Természettudományok Kémiai tudományok előadáskivonat reactive polymeric nanoparticles cross-linking polymerization
Megjelenés:	Technical proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show : NSTI Nanotech 2007, Santa Clara, May 20 - 24. 2007. Vol. 2. - p. 172-175. -
További szerzők:	Hartmann, John F. Borbély János (1950-) (vegyész)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM013449
Első szerző:	Keczánné Üveges Andrea (vegyész)
Cím:	Synthesis of crosslinked polymer nanoparticles suitable for the formation of nanolayer organic films / Andrea Uveges, John F. Hartmann, Lajos Daroczi, Janos Borbely
Dátum:	2009
ISSN:	0303-402X
Megjegyzések:	Free radical crosslinking copolymerization of styrene and ethylene glycol dimethacrylate (nST/nEGDM in feed=5/5) has been investigated in toluene. Variation of the reaction conditions allows the formation of macromolecules with low molecular weight (21.6 kDa and 12 nm in diameter), perfectly soluble branched particles in the early stage of the polymerization. Elongation of the reaction time leads to the formation of soluble/swelling microgels with medium molecular weight (156 kDa and 41-120 nm) and, finally, swelling/particularly soluble colloidal polymer particles with very high molecular weight (3.6 MDa and 59?324 nm). Conversion, molecular weight [by gel permeation chromatography (GPC)], ratio of pendant vinyl groups [by nuclear magnetic resonance (NMR)], size of nanoparticles in swollen [by dynamic light scattering (DLS)] and dried state [by transmission electron microscopy (TEM)], morphology [by scanning electron microscopy (SEM)], and nanolayer film formation (by SEM) were measured. The role of reaction conditions in producing different polymer structures and morphologies was demonstrated.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Free radical polymerization Nanoparticles Nanolayer film formation
Megjelenés:	Colloid and Polymer Science. - 287 : 4 (2009), p. 471-479. -
További szerzők:	Hartmann, John F. Daróczi Lajos (1965-) (fizikus) Borbély János (1950-) (vegyész)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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