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001-es BibID:	BIBFORM065795
035-os BibID:	(Scopus)84982737905 (WoS)000383291400044
Első szerző:	Bereczki Helga Fruzsina (vegyész)
Cím:	Sol-gel synthesis, characterization and catalytic activity of silica aerogels functionalized with copper(II) complexes of cyclen and cyclam / Helga Fruzsina Bereczki, Lajos Daróczi, István Fábián, István Lázár
Dátum:	2016
ISSN:	1387-1811
Megjegyzések:	Mesoporous silica aerogels covalently functionalized with Cu(II) complexes of cyclen (1,4,7,10-tetraazacyclododecane) and cyclam (1,4,8,11-tetraazacyclotetradecane), denoted as CuAM12 and CuAM14, respectively, have been first prepared. Monolithic materials were synthesized from alkoxysilane-anchored macrocyclic complexes and TMOS through the base catalyzed sol-gel method followed by a supercritical CO2 drying. Presence of organic moieties in the silica structure was confirmed by FT-IR measurements, the amount of incorporated copper was determined by ICP-OES technique, resulting in 1.310 ? 0.028 and 2.060 ? 0.025 wt% copper for CuAM12 and CuAM14, respectively). Surface morphology was characterized by nitrogen adsorption/desorption porosimetry and scanning electron microscopy. Catalytic activities of the aerogels CuAM12 and CuAM14 were evaluated by oxidation of phenol with eco-friendly reagent hydrogen peroxide, without buffering or using organic co-solvents. Control experiments using unbound macrocyclic complexes in the homogenous phase were also conducted. Surprisingly, results revealed that the functionalized aerogels' turnover frequencies (TOF) were approximately 7-15 times higher than that of the free complexes in the homogeneous phase. The increase was attributed to the confinement effect. Reusability studies showed that the catalysts remained active even after four cycles completed. Certain reduction of catalytic activity was observed in the repeated cycles, which was the combined effect of poor mechanical properties of the aerogel, splitting off and leaching of the less-bound surface macrocycles, and extensive adsorption of the oxidation products.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban mesoporous silica aerogel covalently bound cyclam and cyclen complex heterogeneous catalysis confinement effect
Megjelenés:	Microporous and Mesoporous Materials 234 (2016), p. 392-400. -
További szerzők:	Daróczi Lajos (1965-) (fizikus) Fábián István (1956-) (vegyész) Lázár István (1959-) (vegyész)
Pályázati támogatás:	105156 OTKA TÁMOP-4.2.2.A-11/1/KONV-2012-0036 TÁMOP
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM052653
Első szerző:	Lázár István (vegyész)
Cím:	Synthesis and study of new functionalized silica aerogel poly(methyl methacrylate) composites for biomedical use / István Lázár, Helga Fruzsina Bereczki, Sándor Manó, Lajos Daróczi, György Deák, István Fábián, Zoltán Csernátony
Dátum:	2015
ISSN:	0272-8397
Megjegyzések:	Monolithic silica aerogels are nanostructured solids characterized with exceptionally high porosity and specific surface area. Although their strength can be improved by surface treatment with polymers, none of them has been tested yet as a filler in biocompatible polymer composites. The new aerogel-poly(methyl methacrylate) composites were prepared by free radi- cal bulk polymerization of neat methyl methacrylate in the presence of natural and functionalized silica aero- gels at 60 C, using cumene hydroperoxide initiator and 4, N , N -trimethyl-aniline redox pair. Synthetic conditions were set to be most similar to the setting of orthope- dic bone cements. Structures, compositions, and molecular weight distributions were determined by scanning electron microscopy, combustion analysis, and gel permeation chromatography, respectively. Compressive strength, Shore D hardness and Gard- ner's impact strength were measured, and the fracture properties were compared to the matrices. All four aerogel fillers resulted in significant enhancement in compressive strength, reaching a maximum value of 123 MPa. Dissolution of H103PC-1 natural and H106PB-1 C16 modified aerogel containing specimens in simulated body fluid occurred in 20 days, leaving porous surfaces behind, which may give rise to higher tissue adhesion potential in bone cements. Heat treated silica aerogel in H112PA-1 showed no leaching out, and its composites might be usefull in high-load technical applications.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Doktori iskola
Megjelenés:	Polymer Composites 36 : 2 (2015), p. 348-358. -
További szerzők:	Bereczki Helga Fruzsina (1986-) (vegyész) Manó Sándor (1977-) (gépészmérnök, számítógépes tervezőmérnök) Daróczi Lajos (1965-) (fizikus) Deák György (1954-) (polimer kémikus) Fábián István (1956-) (vegyész) Csernátony Zoltán (1959-2023) (ortopéd sebész, traumatológus)
Pályázati támogatás:	TÁMOP-4.2.2/B-10/1-2010-0024 TÁMOP Kémiai Tudományok Doktori Iskola TÁMOP-4.2.2.A-11/1/KONV-2012-0036 TÁMOP 76834 OTKA
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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