RESUMEN
Fluoroalkyl end-capped acrylic acid oligomers/fullerenes nanocomposites reacted smoothly with tetraethoxysilane (TEOS) and silica nanoparticles under alkaline conditions to give fluoroalkyl end-capped oligomers/silica composites-encapsulated fullerenes. Interestingly, these isolated fluorinated composites were found to afford nanometer size-controlled colloidal particles with a good dispersibility in a variety of organic solvents including water. More interestingly, these fluorinated silica nanocomposites-encapsulated fullerenes were applied to a new type of surface modification agent, and these nanocomposites were able to disperse well above the poly(methyl methacrylate) films to exhibit not only surface active property imparted by fluorine but also a unique characteristic related to fullerenes in the nanocomposites on the surface, effectively.
Asunto(s)
Acrilatos/química , Fulerenos/química , Hidrocarburos Fluorados/química , Nanocompuestos/química , Dióxido de Silicio/química , Coloides/química , Membranas Artificiales , Tamaño de la Partícula , Polimetil Metacrilato/químicaRESUMEN
The flexural strength and flexural modulus of an experimental metal-resin composite, which used Ag-In alloy particle as the filler, were evaluated. The effect of acid treatment and heat treatment on the Ag-In alloy particle was investigated. The flexural strength of the experimental metal-resin composites ranged from 65.5 MPa to 91.0 MPa. The flexural strength of the metal-resin composite increased with the temperature of the heat treatment until 350 degrees C, but its effect varied with the concentrations of HCl of the acid treatment. A metal-resin composite, which used acid-treated and 350 degrees C heat-treated Ag-In alloy fillers, matched the requirement of strength of ISO 4049. The average of flexural modulus of the experimental metal-resin composite was 9.1 GPa. The flexural modulus of the metal-resin composite did not vary with the treatment conditions of the metal filler. The flexural modulus of a metal-resin composite, which used Ag-In alloy particle as the filler, was lower than that of Ag-Sn alloy metal-resin composite, which was reported previously. However, the flexural strength of the Ag-In alloy metal-resin composite was similar to that of Ag-Sn alloy metal-resin composite. We can control a flexural modulus of a metal-resin composite without decreasing flexural strength by choosing filler materials.
Asunto(s)
Resinas Compuestas/química , Aleaciones Dentales/química , Algoritmos , Análisis de Varianza , Elasticidad , Microanálisis por Sonda Electrónica , Aleaciones de Oro/química , Calor , Humanos , Ácido Clorhídrico/química , Indio/química , Ensayo de Materiales , Metacrilatos/química , Tamaño de la Partícula , Docilidad , Polietilenglicoles/química , Ácidos Polimetacrílicos/química , Poliuretanos/química , Cementos de Resina/química , Estrés Mecánico , Propiedades de Superficie , Estaño/químicaRESUMEN
Ten 35Ag-30Pd-20Au-15Cu alloys containing 0.00, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 2.00, 4.00, or 6.00% Ga were experimentally prepared to investigate the effect of Ga on their mechanical properties in addition to their use for denture frameworks, connectors and clasps. The effect of Ga addition on the mechanical properties was marked with a significant increase in the tensile strength, 0.2% off-set proof stress (proof stress) and Vickers hardness observed at low Ga contents (0.25-2.00%). On the other hand, the elongation significantly decreased with the addition of Ga at all contents used in this study. The tensile strength, proof stress and Vickers hardness of the 35Ag-30Pd-20Au-15Cu alloys containing 0.25-2.00% Ga were in the range of 809-957 MPa, 669-857 MPa and 260-301 MPa, respectively. These values are similar to those of Co-Cr alloys, suggesting that 0.25-2.00% Ga alloys can be used for denture frameworks, clasps and connectors.
