RESUMEN
Nanocrystalline silver sulfide was successfully synthesized at room temperature and ambient pressure via a novel, safe, convenient and inexpensive redox reaction, using silver oxide, sulfur and polyformaldehyde as reactants and ethylenediamine as solvent. The products were characterized with XPS, XRD and TEM. XRD spectrum demonstrates a monoclinic Ag2S; TEM shows the products are rod-like nanoparticles with average diameter of 100 nm, its corresponding SAED reveals clear diffraction spots indexed as (120) and (303); XPS confirms the formation of Ag2S and indicates the sample's surface stoichiometry of Ag:S=1:0.453. The control experiments show polyformaldehyde and ethylenediamine are both important in the formation of products. Ethylenediamine accelerates the reactions via dissolving silver oxide and sulfur and neutralizing the by-product formic acid.
Asunto(s)
Nanopartículas/química , Espectroscopía de Fotoelectrones/métodos , Compuestos de Plata/química , Sulfuros/química , Etilenodiaminas/química , Formaldehído/química , Microscopía Electrónica de Transmisión , Nanopartículas/ultraestructura , Óxidos/química , Polímeros/química , Compuestos de Plata/síntesis química , Solventes/química , Sulfuros/síntesis química , Azufre/química , Temperatura , Difracción de Rayos XRESUMEN
Nonsteroidal antiinflammatory drug, probenecid, was covalently linked with 2-hydroxyethyl methacrylate (HEMA). The drug linked HEMA(abbreviated as HP) can be copolymerized with methy methacrylate (MMA) to obtain polymeric drug nanomicrospheres in ethanol/water system. Polymers were characterized with 1H-NMR, FTIR, GPC and TEM. The results showed that probenecid was linked with HEMA by ester bond, the microspheres were composed of copolymer of HP and MMA, whose statistical average diameters were (90 +/- 5) nm, containing 47.4% HP, and drug content was high.
Asunto(s)
Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Probenecid/administración & dosificación , Adyuvantes Farmacéuticos/administración & dosificación , Adyuvantes Farmacéuticos/síntesis química , Materiales Biocompatibles , Reactivos de Enlaces Cruzados/química , Ensayo de Materiales , Metacrilatos/administración & dosificación , Metacrilatos/química , Microesferas , Polímeros/síntesis químicaRESUMEN
After nano-particles (ZnO) had been encapsulated by a kind of water-soluble cellulose Hydoxyl-Propyl-Methyl Cellulose (HPMC), then methyl methacrylate was grafted onto the surface of them. Thus the surface of nano-ZnO had been successfully modified. FTIR, DTA and TEM were utilized to confirm the results. FTIR shows that HPMC was adsorbed onto the surface of ZnO, and PMMA was also grafted onto its surface, DTA says that the heat stability of HPMC, HPMC-g-PMMA and ZnO/HPMC-g-PMMA increased greatly, TEM photo demonstrates that polymer adhered onto the surface of nano-ZnO which was encapsulated by a layer of film-like polymer.
