Search results for "Epoxy"
showing 10 items of 384 documents
In vitro antibacterial activity of endodontic sealers
2004
Summary Objectives To evaluate the antibacterial activity of four endodontic sealers: one epoxy resin sealer (AH Plus), two zinc oxide eugenol (ZOE)-based sealers (Endomethasone, Pulp Canal Sealer), and one sealer containing both ZOE and orthophenilphenol (Vcanalare). Methods A direct contact test (DCT) was performed. A 10 μl suspension of Enterococcus faecalis was placed on the test material 20 min, 24 h and 7 days after mixing. Bacteria were allowed to directly contact the sealers for 1 h at 37 °C. Bacterial growth was then spectrophotometrically measured every 30 min for 7 h, and again after 24 h as well. Results All freshly mixed sealers showed complete inhibition of bacterial growth. S…
Preliminary studies on nanocomposite based on high quality Silicon Carbide nanofibers
2012
Nanocomposites are nowadays the most promising new materials due to their unique properties (such as high mechanical strength, chemical and thermal resistance). The nanocomposite matrix is blended with a nanostructured filler. In this study, Silicon Carbide nanofibers (NFSiC) and their bundles were tested as a reinforcement of two epoxy resins: EPIKOTE 828 and EL 20. PAP-4 (33 phr) and P-900 (40 phr) were used as hardeners in the two cases, respectively. Several samples were prepared in the range between 0.1 and 5 % wt for both types of resins and fillers (NFSiC and NFSiC bundles). Mechanical and electrical properties were tested. The fillers were obtained using a new simple, fast, low-cost…
The adaptation of mechanically softened gutta-percha to the canal walls in the presence or absence of smear layer: a scanning electron microscopic st…
1995
Summary The objective of this study was to compare the adaptation of mechanically softened gutta-percha to the root canal wall in the presence and absence of smear layer. The root canals of 20 freshly extracted human maxillary incisors were cleaned and shaped. Prior to obturation, 10 root canals were irrigated with 20 ml of 50% citric acid followed by 20 ml of 5.25% sodium hypochlorite. All canals were obturated with mechanical compaction of gutta-percha and AH-26 sealer. After 72h, each tooth was fractured in half. Scanning electron microscopy demonstrated that the sealer had formed a continuous layer in contact with the canal walls, becoming progressively thinner towards the apex. The sea…
Effect of sodium bicarbonate treatment on mechanical properties of flax-reinforced epoxy composite materials
2017
This paper deals with the evaluation of the effect of an eco-friendly and cost-effective surface treatment based on the use of sodium bicarbonate on the mechanical properties of flax-reinforced epoxy composites. To this aim, unidirectional fabrics were soaked for five days in 5 and 10% in weight of sodium bicarbonate solution at 25℃. Quasi-static and dynamic mechanical tests were performed and the fracture surfaces of the composites were analyzed through scanning electron microscopy. Results evidenced that this treatment improves the fiber–matrix adhesion thus increasing the performances of the composites. Treating the fabrics with 10% w/w of bicarbonate solution leads to improvements of ∼…
Dioxidomolybdenum(VI) and -tungsten(VI) complexes with tripodal amino bisphenolate ligands as epoxidation and oxo-transfer catalysts
2017
The molybdenum(VI) and tungsten(VI) complexes [MO2(L)] (M = Mo (1), W (2), H2L = bis(2-hydroxy-3,5-di-tert-butybenzyl)morpholinylethylamine) were synthesized and the complexes were used to catalyze oxotransfer reactions, viz. sulfoxidation, epoxidation and benzoin oxidation. For comparison, the same reactions were catalyzed using the known complexes [MO2(L′)] (M = Mo (3), W (4), H2L′ = bis(2-hydroxy-3,5-di-tert-butybenzyl)ethanolamine) and [MO2(L″)] (M = Mo (5), W (6), H2L″ = bis(2-hydroxy-3,5-di-tert-butybenzyl)diethyleneglycolamine). The oxo atom transfer activity between DMSO and benzoin at 120 °C was identical for all studied catalysts. Reasonable catalytic activity was observed for sul…
Polymer-based materials modified with magnetite nanoparticles for enrichment of phospholipids
2018
[EN] A polymeric material modified with magnetic nanoparticles (MNPs) has been synthesized and evaluated as sorbent both for solid-phase extraction (SPE) and dispersive magnetic solid-phase extraction (MSPE) of phospholipids (PLs) in human milk samples. The synthesized sorbent was characterized by scanning electron microscopy and its iron content was also determined. Several experimental variables that affect the extraction performance (e.g. loading solvent, breakthrough volume and loading capacity) were investigated and a comparison between conventional SPE and MSPE modalities was done. The proposed method was satisfactorily applied to the analysis of PLs in human milk fat extracts in diff…
CCDC 994085: Experimental Crystal Structure Determination
2015
Related Article: Christoph Reiter, Tony Fröhlich, Maen Zeino, Manfred Marschall, Hanife Bahsi, Maria Leidenberger, Oliver Friedrich, Barbara Kappes, Frank Hampel, Thomas Efferth, Svetlana B. Tsogoeva|2015|Eur.J.Med.Chem.|97|164|doi:10.1016/j.ejmech.2015.04.053
CCDC 1816140: Experimental Crystal Structure Determination
2018
Related Article: Aysun Çapcı Karagöz, Christoph Reiter, Ean-Jeong Seo, Lisa Gruber, Friedrich Hahn, Maria Leidenberger, Volker Klein, Frank Hampel, Oliver Friedrich, Manfred Marschall, Barbara Kappes, Thomas Efferth, Svetlana B. Tsogoeva|2018|Bioorg.Med.Chem.|26|3610|doi:10.1016/j.bmc.2018.05.041
CCDC 1894341: Experimental Crystal Structure Determination
2019
Related Article: Alexander Lipp, Maximilian Selt, Dorota Ferenc, Dieter Schollmeyer, Siegfried R. Waldvogel, Till Opatz|2019|Org.Lett.|21|1828|doi:10.1021/acs.orglett.9b00419
CCDC 1831235: Experimental Crystal Structure Determination
2018
Related Article: Alexander Lipp, Dorota Ferenc, Christoph Gütz, Mario Geffe, Nina Vierengel, Dieter Schollmeyer, Hans J. Schäfer, Siegfried R. Waldvogel, Till Opatz|2018|Angew.Chem.,Int.Ed.|57|11055|doi:10.1002/anie.201803887