Showing papers on "Glass microsphere published in 2012"

Optical super-resolution by high-index liquid-immersed microspheres

Abstract: It is experimentally shown that barium titanate glass microspheres with diameters (D) in the range 2–220 μm and with high refractive index (n ∼ 1.9–2.1) can be used for super-resolution imaging of liquid-immersed nanostructures. Using micron-scale microspheres, we demonstrate an ability to discern the shape of a pattern with a minimum feature size of ∼λ/7, where λ is the illumination wavelength. For spheres with D > 50 μm, the discernible feature sizes were found to increase to ∼λ/4. Detailed data on the resolution, magnification, and field-of-view are presented. This imaging technique can be used in biomedical microscopy, microfluidics, and nanophotonics applications.

Dynamic mechanical behavior of syntactic iron foams with glass microspheres

Abstract: In this work, the mechanical behavior of syntactic foams made of hollow glass microspheres mixed in an iron matrix was investigated. This type of material is interesting since, when compared to other types of metal foams, it offers greatly increased quasi-static compressive strength, though at lower maximum porosity and thus higher density. Moreover it maintains the advantages and useful properties of metal foams such as thermal and environmental resistance. In particular, the strain-rate sensitivity response was studied. The experimental characterization was performed by means of compression tests at three strain-rate levels: at the highest strain-rate level a SHPB was used. Type and content of glass microspheres were also studied. The experimental results showed that the compression behavior of syntactic foams, similarly to the other types of foams, is strongly affected by all the examined factors. For what concerns the strain-rate, it was found to increase material characteristics in almost all cases. The influence of the matrix behavior on the composite was identified as the determining parameter in this respect. In order to evaluate the results obtained with the described tests campaign, the experimental data were further elaborated by means of an empirical analytical strain-rate sensitive model. The dependency of the material response on model parameters was widely discussed.

Thermal, dielectric and compressive properties of hollow glass microsphere filled epoxy-matrix composites:

Abstract: Four types of hollow glass microspheres, having the density of 0.125–0.60 g/cm3, were filled into epoxy-matrix, and volume fraction of hollow glass microsphere was varied from 0% to 60%. The therma...

Thermal expansion behavior of hollow glass particle/vinyl ester composites

Abstract: Ceramic particle-reinforced composites have better dimensional stability than the matrix polymer at high temperatures. In hollow-particle filled composites (syntactic foams), the coefficient of thermal expansion (CTE) can be controlled by two parameters simultaneously: wall thickness and volume fraction of particles, which are explored in this study. The CTE was experimentally measured to be up to 60.4 % lower than the matrix material with the addition of glass microballoons for the twelve compositions of syntactic foams characterized using a thermomechanical analyzer. The CTE values have a stronger dependence on particle volume fraction than the wall thickness within the range of parameters explored. The experimental trends are analyzed by using Turner’s and Kerner’s models modified for syntactic foams. The results from the modified Turner’s model show close correlation with the experimental values with a maximum difference of ±15 %. Parametric studies show that syntactic foams of a wide range of densities can be tailored to obtain the same CTE value. The experimental and theoretical results are helpful in developing syntactic foams with desired properties for thermal applications.

Syntactic Iron Foams - On Deformation Mechanisms and Strain-Rate Dependence of Compressive Properties

Abstract: Syntactic iron foams are produced by metal injection moulding from pure Fe powder and two grades of commercial glass microspheres. Mechanical performance of samples containing 5/10/13 wt% of microspheres is compared to unfilled reference material properties at strain-rates covering 6 orders of magnitude, including Split Hopkinson Pressure Bar (SHPB) experiments. Complex mechanical behavior including strengthening effects of microspheres leading to a plateau strength level which is nearly independent of porosity as well as strain-rate sensitivity of compressive properties are observed. Typical plateau onset stress levels exceed equivalent characteristics of most comparable cellular metallic materials, reaching between approximately 220 and 270 MPa under quasi-static conditions, depending on amount and type of added microspheres. A qualitative explanation of significant events in the deformation sequence as reflected in the stress–strain-curve is offered and discussed in the context of existing studies on syntactic foams. A course for further investigations to verify this hypothesis is suggested.

Influence of hollow glass microspheres on the mechanical and physical properties and cost of particle reinforced polymer composites

Abstract: The goal of the study was to find a cost-effective composition of a particle reinforced composite that is light in weight but has sufficient mechanical properties. The matrix of the particulate composite is unsaturated polyester resin that is reinforced with alumina trihydrate particles. Part of the alumina trihydrate proportion was replaced with hollow glass microspheres to reduce weight and save costs. In order to find out the influence of the light filler on the physical and mechanical properties of composites, materials with different percentages of the light filler were prepared. Test specimens were cut from moulded sheets that were fabricated with vacuum assisted extruder. Tensile strength, indentation hardness measured with a Barcol impressor, and density were determined. Based on the experimental data a multi-criteria optimization problem was formulated and solved to find the optimal design of the material. Artificial neural networks and a hybrid genetic algorithm were used. The optimal solution is given as a Pareto curve to represent the distinction between the density and selected mechanical properties of the composite material. The composite material filled with 6% hollow glass microspheres showed 3% loss in the tensile strength and 26% loss in the surface hardness compared to the composition without the filler. The weight decreased by 13% compared with the initial composition. The addition of hollow glass microspheres did not lower the net value of the material, it increased 7%.

Waterborne heat-insulating flame-retardant multifunctional nano coating and preparation method thereof

Abstract: The invention relates to a waterborne heat-insulating flame-retardant multifunctional nano coating and a preparation method thereof. The coating consists of the following components in part by weight: 48 to 52 parts of waterborne resin and 30 to 50 parts of nano pigment fillers (nano titanium dioxide, nano titanium dioxide-coated hollow glass microspheres, nano titanium dioxide-coated hollow ceramic microspheres and nano antimony-doped tin dioxide (ATO) particles), size and auxiliary materials such as film-forming additive and coupling agent. The preparation method includes the steps that: the nano fillers and the size are first dipped into the waterborne resin, the auxiliary materials are then sequentially added and stirred, and thereby the heat-insulating flame-retardant multifunctional nano coating is obtained. The processing technique is simple, the component proportion is reasonable, and the prepared coating has the advantages of high heat resistance, high reflectivity, high radiative heat conductivity, certain fire resistance, high-efficient heat insulation, excellent mechanical and chemical properties, environment-friendliness, stain resistance, flame retardance and energy saving. The coating can be coated on outside facilities such as outer walls and building roofs.

Processing and mechanical characterization of carbon nanotube reinforced syntactic foams

Abstract: Carbon nanotube reinforced, syntactic foams are processed and evaluated for compressive and dynamic mechanical properties. Vertically aligned nanotubes were first grown on the microballoons surface and added into the epoxy system. The weight percent of the nanotubes were varied from 0% to 0.8%. The properties of carbon nanotube reinforced syntactic foams are compared with neat syntactic foams that did not contain nanotubes. Results show improvement in compressive modulus and damping coefficient values by 35%–41% and 10%–104%, respectively. Compressive strength, elastic modulus and glass transition temperature remained largely unchanged for most compositions.

Surface Modification of Hollow Glass Microspheres

Abstract: Hollow Glass Microspheres are high-strength, low-density additives made from water resistant and chemically-stable soda-lime-borosilicate glass. These hollow glass microspheres offer a variety of advantages over conventional irregularly-shaped mineral fillers or glass fiber. Their spherical shape helps reduce resin content in a variety of applications. They also create a ball bearing effect that can result in higher filler loading and improved flow. In this research, amine terminated hollow glass microspheres were prepared by adopting three different routes. The results were investigated using FT-IR and SEM to establish the formation of amine groups and observe the morphological structure of the modified HGMs. The results obtained were used to select a suitable less toxic and environmental friendly modification method based on the chemicals used.

Waterproof thermal insulation coating composition and preparation method thereof

Abstract: The invention relates to a waterproof thermal insulation coating composition, which comprises an aggregates, a substrate, an auxiliary filling and an assistant, and is characterized in that the aggregates are hollow glass microspheres, and the substrate is silicone acrylic emulsion; in the thermal insulation coating composition, 6-18 parts by mass of hollow glass microspheres and 21-27 parts by mass of silicone acrylic emulsion are provided. According to the invention, the silicon acrylic emulsion is selected, so that the thermal insulation coating has excellent thermal insulation property, and good waterproof and antifouling performance, and the waterproof and antifouling performance is more excellent for fluorine-containing silicone acrylic emulsion.

Optical microresonator based on hollow sphere with porous wall for chemical sensing.

Abstract: A porous-wall hollow glass microsphere (PW-HGM) was investigated as an optical resonator for chemical vapor sensing A single mode optical fiber taper was used to interrogate the microresonator Adsorption of chemical molecules into the nanosized pores induced a refractive index change of the thin wall and thus a shift in its resonance spectrum The PW-HGM resonator had shown higher vapor detection sensitivity in comparison with a solid microsphere under similar test conditions

Foams in Glass Manufacturing

Abstract: The glass manufacturing industry provides products critical to a wide range of applications, including (i) container glass for consumer products, (ii) flat glass for automotive and buildings, (iii) fiberglass for thermal insulation, roofing, and reinforced composite materials, and (iv) specialty glass such as liquid crystal displays, optical communication, and lighting, to name a few [1]. Container glass represents more than 65% of the mass of glass produced worldwide [2]. In 2009, the US glass industry produced about 20 millions tons of glass or 20% of the global production and employed about 91,000 people for industry revenues of $21.6 billion [3]. During the past two decades, business competition and economic challenges have forced glass manufacturers worldwide to increase productivity and product quality. They have also faced ever more stringent regulations for combustion-generated pollutant emissions. Soda-lime-silica glass, also known as soda-lime glass, is the most common type of glass used for containers, lighting devices, and windows for buildings and automotive applications [4, 5]. It typically contains 60–75 wt% SiO 2 , 12–18 wt% Na 2 O, and 5–12 wt% CaO. Borosilicate glass is another common type of glass used for its chemical durability and its low thermal expansion coefficient as glassware in the chemical industry and laboratories, as flat panel display, and as cookware [4]. Their typical composition contains 70–80 wt% SiO 2 , 7–13 wt% B 2 O 3 , 4–8 wt% Na 2 O and K 2 O, and 2–7 wt% Al 2 O 3 [4]. In addition, E-glasses are used in fiberglass for thermal and acoustic insulation for buildings as well as for textile and reinforced plastics. They are aluminosilicate glass with typical composition of 52–6 wt%

Properties of rigid polyurethane foams filled with glass microspheres

Abstract: The effect of hollow glass microspheres with a density of 125 kg/m3 on the properties of low-density (54-90 kg/m3) rigid polyurethane foams is investigated. The thermal expansion coefficient of the foams and their properties in tension and compression in relation to the content of the microspheres (0.5-5 wt.%) are determined. An increase in the characteristics of the material in compression in the foam rise direction with increasing content of filler is revealed. The limiting content of the microspheres above which the mechanical characteristics of the filled foams begin to decrease is found. The distribution of the microspheres in elements of the cellular structure of the polyurethane foams is examined.

Thermoplastic resin composite containing hollow glass microspheres

Abstract: A thermoplastic resin composite with improved specific flexural strength, and a molded body containing the thermoplastic resin composite A thermoplastic resin composite containing a resin component which is a polyamide resin or polypropylene resin, and hollow glass microspheres, wherein the hollow glass microspheres are surface treated with from 05 to 3 mass % of a silane coupling agent and from 1 to 5 mass % of a synthetic resin emulsion, based on 100 mass % of hollow glass microspheres

Dynamic bioactive nanofiber scaffolding

Abstract: A resorbable bone graft scaffold material, including a plurality of overlapping and interlocking fibers defining a scaffold structure, plurality of pores distributed throughout the scaffold, and a plurality of glass microspheres distributed throughout the pores. The fibers are characterized by fiber diameters ranging from about 5 nanometers to about 100 micrometers, and the fibers are a bioactive, resorbable material. The fibers generally contribute about 20 to about 40 weight percent of the scaffold material, with the microspheres contributing the balance.

Heat reflection paint with hollow glass microballoon

Abstract: The invention relates to a heat reflection paint with hollow glass microballoons, which comprises a surface paint and a prime paint, wherein the surface paint at least comprises silicone-acrylate emulsion, rutile type titanium dioxide and nano functional composite materials, and the prime paint at least comprises silicone-acrylate emulsion, hollow glass microballoon, hollow inorganic fiber and engineering cellulose. In the invention, the silicone-acrylate emulsion synthesized by the interpenetrating network technology has high diaphaneity and low absorbency, thereby ensuring the excellent weather fastness, the durability and the anti-stain performance of the paint film and maintaining the heat reflectivity and the heat-shielding performance of the coating for long. The synthesized nano functional composite materials have strong sunlight reflection effects, and the reflectivity can be more than 0.9, thereby ensuring the excellent reflective insulation function of the paint film. The selected special high molecular materials and the vacuum glass microballoons can effectively prevent the permeation of heat.

Thermo-Optical Tuning of Whispering Gallery Modes in Erbium:Ytterbium Doped Glass Microspheres to Arbitrary Probe Wavelengths

Abstract: We present experimental results on an all-optical, thermally-assisted technique for broad range tuning of microsphere cavity resonance modes to arbitrary probe wavelengths. An erbium:ytterbium co-doped phosphate glass (Schott IOG-2) microsphere is pumped at 978 nm via the supporting stem and the heat generated by absorption of the pump light expands the cavity and changes the refractive index. This is a robust tuning method that decouples the pump from the probe and allows fine tuning of the microsphere's whispering gallery modes. Pump/probe experiments were performed to demonstrate thermo-optical tuning to specific probe wavelengths, including the 5S1/2 F= 3 to 5P3/2 F'= 4 laser cooling transition of rubidium-85. This is of particular interest for cavity quantum electrodynamics (QED)-type experiments, while the broad tuning range achievable is useful for integrated photonic devices, including sensors and modulators.

Contrast on tensile and flexural properties of glass powder reinforced epoxy composites: pilot study

Abstract: Epoxy resin was filled with glass powder to optimize the tensile and flexural strength of the composite for structural applications by a research centre in the University of Southern Queensland (USQ). In order to reduce costs, the centre wishes to fill as much glass microspheres as possible subject to maintaining sufficient strength of the composites in structural applications. This project varies the percentage by weight of the glass powder in the composites. After casting the composites to the moulds, they were cured at ambient conditions for 24 hours. They were then post-cured in a conventional oven and subjected to tensile and flexural tests. The contribution of the study was that if tensile and flexural properties were the most important factors to be considered in the applications of the composites, the maximum amount of glass powder can be added to the resin will be five (5) percent. It was also found that the fractured surfaces examined under scanning electron microscope were correlated with the tensile and flexural strength It is also hoped that the discussion and results in this work would not only contribute towards the development of glass powder reinforced epoxy composites with better material properties, but also useful for the investigations of tensile and flexural properties in other composites.

Processing and properties of syntactic foams reinforced with carbon nanotubes

Abstract: This article presents synthesis and mechanical characterization of carbon nanotube (CNT)-reinforced syntactic foams. Following a dispersion approach (comprising ultrasonic, calendering, and vacuum centrifugal mixing), single- and multi-walled functionalized CNTs (FCNTs) were incorporated into two foam composites containing various commercially available microballoon grades (S38HS, S60HS, and H50 from 3M). The FCNT-reinforced composites were tested for compressive strength and apparent shear strength before and after hot/wet conditioning. The results showed that the FCNT-reinforced composites' mechanical properties depended on the vacuum pressure used during processing. Compared with pristine and commercially available syntactic foam (EC-3500 from 3M), the FCNT-reinforced composites processed at high vacuum (0.2 kPa) showed significant increase in compressive strength and apparent shear strength before and after hot/wet conditioning. Dynamic mechanical analysis showed an increase of about 22°C in glass transition temperature for composites processed at high vacuum with 0.5 wt % FCNT and 45 wt % S38HS–5 wt % S60HS microballoons. Thermogravimetric analysis indicated water absorption and lower decomposition temperature for the FCNT-reinforced composite mixed at atmospheric pressure, whereas no significant change was observed for the compound processed at high vacuum. Fracture analysis showed matrix failure for the composite processed at high vacuum and microballoon crushing for the composite mixed at atmospheric pressure. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Super-resolution imaging by high-index microspheres immersed in a liquid

Abstract: We demonstrate that the super-resolution imaging of a commercial Blu-ray® disk containing a one-dimensional array of 200 nm width stripes separated by 100 nm width grooves can be achieved using high-index microspheres in a liquid environment. By using barium titanate glass microspheres (2–20 μm diameters) with index around 1.9 totally immersed in isopropanol with index 1.37 we demonstrate better than λ/6 far field resolution, where λ= 600 nm is the peak wavelength of the white-light illumination system. The results of this work can be used in biomedical microscopy, microfluidics and nanophotonics applications for imaging individual cells and/or nanoparticles in a liquid environment.

Preparation method of polymer dispersed liquid crystal film material

Abstract: The invention belongs to the technical field of liquid crystal application and provides a preparation method of a polymer dispersed liquid crystal (PDLC) film material. The method comprises the following steps that: liquid crystal and photopolymerisable monomer are mixed according to the mass ratio of 3:2-1:4, the content of the liquid crystal is 30-60% of the total mass, the content of an added photoinitiator is 0.1-10% of the total mass of the photopolymerisable monomer, and the content of glass microspheres is 0.1-10% of the total mass of the liquid crystal and the photopolymerisable monomer; the liquid crystal, the photopolymerisable monomer, the photoinitiator and the glass microspheres are uniformly stirred, and then are clamped between two pieces of conductive plastic films plated with indium tin oxide, and extruded by a rolling shaft to form a thin layer with the thickness being 0.5-40 micrometers; and with the temperature being 0-25 DEG C higher than the clearing point of the liquid crystal phase of the photopolymerisable monomer/liquid crystal composite material, ultraviolet light with the light intensity being 1-20mw/cm2 is used for irradiating for 1-20 minutes so as to prepare the polymer dispersed liquid crystal film.

On-chip fabrication of air-bubble-containing Nd3+-doped tellurite glass microsphere for laser emission

Abstract: We fabricated an air-bubble-containing glass microsphere on a substrate by using localized heating technique. Nd3+-doped tellurite glass cullets on a substrate were melted by a CW-Ti:sapphire laser at the wavelength of 810 nm and with the power density of more than 4.8 MW/cm2 to obtain tellurite glass microspheres with the diameter of 5 to 200 μm. The localized heating technique using laser is useful to form a bubble at a certain place in the microsphere. Both air-bubble-containing and bubble-free spheres showed lasing actions at around the wavelength of 1065 nm. The average laser thresholds of the air-bubble-containing and bubble-free microspheres with the size of 20-50 μm were 0.78 mW and 5.25 mW, respectively.

Prussian blue nano-scale hollow olivary microballoons

Abstract: The invention discloses prussian blue nano-scale hollow olivary microballoons, and belongs to the technical field of prussian blue materials. A preparation method of the prussian blue nano-scale hollow olivary microballoons comprises the following steps that 1, acrylamide as a monomer, N,N'-methylenebisacrylamide as a cross-linking agent, ammonium persulfate as an initiator and ethanol as a solvent are prepared into crosslinked polyacrylamide hydrogel microballoons by a dispersion polymerization technology; 2, hydrogel microballoon/ethanol suspending liquid is added with a Fe salt aqueoussolution; 3 the mixed solution obtained by the step 2 is stirred violently for one night so that the crosslinked polyacrylamide hydrogel microballoons swelled by Fe deform; 4, a potassium ferrocyanide aqueous solution is added dropwisely into the mixed solution treated by the step 3 to form prussian blue shells; and 5, the solvent is removed so that the prussian blue nano-scale hollow olivarymicroballoons are obtained. The preparation method of the prussian blue nano-scale hollow olivary microballoons has the advantages of simple operation, low cost, good adaptability for large-scale production, and controllability of microballoon sizes. The prussian blue nano-scale hollow olivary microballoons have nano-scale short axis sizes and micron-scale long axis sizes, and can be utilized widely for drug slow release, sensors, electrode materials and the like.

Powder comprising polymer-coated glass particles

Abstract: Composite particles comprising core particles completely or partially coated with a precipitated polymer, where the d 50 median diameter of the core particles is from 3 to 100 μm and wherein the glass core particle material is at least one selected from the group consisting of a solid glass bead, a hollow glass bead, a porous glass bead, and a foamed glass particle. A method to prepare the particles includes dissolution of a polymer in a solvent and precipitation of the polymer in the presence of a suspension of the core glass particles. Further provided is a layer by layer moulding process employing the composite particles and mouldings obtained therefrom.

High-Q Bismuth-Silicate Nonlinear Glass Microsphere Resonators

Abstract: The fabrication and characterization of a bismuth-silicate glass microsphere resonator has been demonstrated. At wavelengths near 1550 nm, high-modes can be efficiently excited in a 179-μm diameter bismuth-silicate glass microsphere via evanescent coupling using a tapered silica fiber with a waist diameter of circa 2 μm. Resonances with Q-factors as high as were observed. The dependence of the spectral response on variations in the input power level was studied in detail to gain an insight into power-dependent thermal resonance shifts. Because of their high nonlinearity and high- factors, bismuth-silicate glass microspheres offer the potential for robustly assembled fully integrated all-optical switching devices.