If low-density closed-cell foams are used deep in the sea, the high hydrostatic pressures either compress the foam, or fracture the cell faces, so the foam loses its buoyancy. Consequently syntactic foams are used for buoyancy at depth. These contain hollow glass microspheres in a polymer matrix, and have a density less than that of water.

When closed-cell rigid PU foams are subjected to high water pressures, the cell faces fail and the water enters the structure. Mondal and Khakhar showed the pressure vs. loss of buoyancy graph for a foam of density circa 150 kgm−3 was a function of the surfactant used in the foaming process, hence of the thickness (strength) of the cell faces. In a subsequent article they modelled the breakdown process and showed that the threshold pressure for hydraulic collapse occurred when 9% of the cell faces had fractured.

This article comes from sciencedirect edit released

The Hyundai Mobis IP Core Part Development Project finished a 19-month series of tests comparing a PC/ABS material with a new PP material filled with hollow glass microspheres. We were exploring new material formulations that would help reduce overall part weight and costs in the production of instrument panel core parts, research by engineer for the Cockpit Module Design Project.

That using the PP material with hollow glass microspheres achieved a 16.8% reduction in weight, and lowered the finished part cost by a solid 50% (cost of materials in Korea), compared with the same cores made in PC/ABS.

In addition, we experienced improved material flowability and better dimensional stability compared to current talc-filled polypropylene. The change allowed the use of existing tooling, so no capital outlay there, and also reduced part warpage.

This article comes from plasticstoday edit released

Hollow glass microsphere paints allows the glass fusing artist to create a range of hollow glass microsphere fused glass items. Available in range of eleven colors and mixing medium, hollow glass microsphere paints may be applied wet or dry to suitable art glass pieces before fusing in a glass kiln.

This paint is suitable for general glass fusing or fused art glass jewelry. The paints can be mixed to make additional colors. Each color is a fine powder which is suitable for either COE 90 or COE 96 fusing glass.

Using As A Paint

To use as a paint, the powder is mixed with a special hollow glass microspheres paint medium to the thickness of cream. It can then be applied with a paint brush. Using this method, original designs can be created on the glass, with a clear cap being added to obtain the best result.

Separate colors can be used and mixed on the glass if desired. Mix only as much as needed as left over dry paint mix can not be used.

Another method is to paint a piece of glass with hollow glass microspheres paint medium and then sift paint powder onto the glass. The more medium, the more it will produce a translucent water color finish after being fired in a fusing glass kiln. By sifting a range of different colors onto the glass a nice multi-colored hollow glass microsphere finish can be obtained.

Paint can be dry sifted onto a piece of glass with a clear cap added to cover the powder prior to glass fusing. Different colorc can be laid on top of each other to create an original shaded finish. Cap with clear fusing glass prior to fusing in a glass fusing kiln. With a heavy coating of powder the larger the hollow glass microspheres may be. If the hollow glass microspheres are too large then the top glass can be thin and weak.

For the best results the glass should be fused at a fast full fuse at about 1450° F. Slower fusing rates may result in a large number of unwanted hollow glass microspheres. Once fused the glass should be left to cool to room temperature before removing from the glass kiln.

This article comes from jewelry-making-how-to edit released

Microscopic hollow glass microspheres can be used in numerous applications; as an adjusting aid and distancing element of electricity-conducting single components, in microelectronic mechanics, as an abrasion-deterring element in grating components, in mechanical engineering, and as a material for artistic surface design.

A New Adhesive System

The Controltac adhesive system is an innovation in the area of large format graphic films. In this system, approximately 50µm strong films are equipped. In addition to the adhesive, millions of microscopic (40 up to 50µm diameter) hollow glass microspheres are utilized in an exact, regular arrangement.

This is achieved through the preceding microstructuring of the surface. The small hollow glass microspheres create a gliding effect between the adhesive and the area to be adhered, enabling precise alignment of the foil.

The spheres sink into the adhesive layer upon application of stronger pressure, and can then be permanently fixed to the base. This technology enables large formatting foils to be adhered.

Lighter Materials

Another, new application comprises of a composite material of metal and hollow glass microspheres. The new material both shines and feels like solid metal, but at the same time, is remarkably light. In order to achieve this, the metal is poured into hollow glass microspheres measuring 60µm.

If the hollow glass microspheres are unevenly distributed, it results in an even surface, which feels completely smooth like metal. With an irregular distribution of the glass, the material appears as if it were marbled with veins.

Although the material is very porous, it appears completely smooth and weighs very little. With the density of aluminum of 2.7g/cm3 is lowered to 1.2g/cm3. With zinc from 7g/cm3, it is reduced by more than half, namely to 3.1g/cm3.

The Measurement

The image below shows the particle size distribution of hollow glass microspheres, which was attained using the ANALYSETTE 22 (maximum measuring range: 0.1–2100µm). The measurement was carried out using a dry dispersion unit with a modified pressure at the Venturi injectors.

The measuring range was covered from 0.85 up to approximately 116µm. During the assessment of the measuring data, the Mie-theory was used, especially in the area of smaller particle diameters for samples that have a small refractive index.

An already major deviation of the calculation according to Fraunhofer is recognizable. For comparison, a distribution curve from the Fraunhofer approximation was also drawn into the diagram.

This article comes from azom edit released

Hollow Glass Microspheres are near perfect spherical shapes of thin walled glass bubbles that are approximately 50 microns in size. The glass type is amorphous and can come low purity or high purity (Trelleborg) grades.

The key properties of low density hollow glass microspheres are their light weight and strength. Incorporating them into buoyancy products allows Remotely Operated Vehicle (ROV), or Autonomous Underwater Vehicle (AUV) manufacturers to provide buoyancy to vehicles without the use of cumbersome pressure vessels (buoyant structures) because the material itself is buoyant (buoyant material). Some of other applications are as an alternative to conventional fillers and additives such as silica, calcium carbonate, talc, and clay in low dielectric or thermally insulating applications.

The hollow glass microspheres can be incorporated into a wide range of polymer and resin systems and can be customized via surface treatments, material chemistry selection, density specifications, or particle size distribution, thereby being tailored to meet demanding strength, weight and electrical specifications for customers in a variety of markets.

This article comes from trelleborg edit released

Porous wall hollow glass microspheres are provided as a template for formation of nanostructures such as carbon nanotubes, In addition, the carbon nanotubes in combination with the porous wall hollow glass microsphere provides an additional reaction template with respect to carbon nanotubes.

The use of porous wall hollow glass microspheres and its associated pore structures as a template and associated microscale reaction environment for formation of novel compounds. The templating and reaction process can occur on, in and through the porosity of the outer glass microsphere walls as well as within the interior regions of the porous wall hollow glass microspheres, the microspheres provide. Unique nanostructures and compositions may be generated inside the glass microspheres which provide an enclosed protective environment for the materials so formed.

This article comes from google website edit released

The addition of hollow glass microspheres is interesting to reduce the thermal conductivity of the concrete pieces. This work aims to evaluate the concrete with addition of hollow glass microsphere with different combinations of dosage in concrete concerning strength and workability.

Slump tests were performed in each dosage of concrete in order to evaluate the effect of glass microspheres in concrete mix. In each age of curing concrete, bodies-specimens underwent ultrasound to estimate the homogeneity of concrete with hollow glass microspheres, and testing of compressive strength.

The analysis of the results shows that for some formulations, the addition of hollow glass microspheres imparts high mechanical strength to compressive strength above 30MPa at all analyzed cure periods. The workability of the concrete had to be substantially reduced, showing no workability improvement due to the addition of hollow glass microsphere.

This article comes from scientific edit released

Porous-wall hollow glass microspheres are a one-of-the-kind material with many potential uses in security technology.

This work focuses on the development of security inks containing porous-wall hollow glass microspheres, whereby the microspheres serve as storage vessels for a variety of functional materials.

This preliminary work comprises two feasibility studies. One study resulted in the successful aerosol jet deposition of hollow glass microspheres onto a substrate. The other study resulted in the loading of porous-wall hollow glass microspheres with gold nanoparticles. Both studies demonstrate the feasibility of developing and delivering a security ink utilizing porous-wall hollow glass microspheres that are loaded with functional materials. The results encourage the continuation of research to achieve this goal.

This article comes from researchgate edit released

In recent years, composite materials containing hollow glass or ceramic microspheres have attracted considerable attention. These materials have very good heat-insulation characteristics, which are largely defined by special features of absorption and scattering of thermal radiation by thin-walled hollow particles (German and Grinchuk, 2002; Dombrovsky, 2005). The paint coatings containing hollow glass microspheres have already found applications for reducing heat loss from the walls of buildings owing to a decrease in thermal radiation at night.

Infrared radiative properties of a polymer containing hollow glass microspheres are studied by means of the measurements of direc- tional-hemispherical reflectance and transmittance in the wavelength range from 2.6 to 18 lm. The measurements are performed for sev- eral samples containing different series of microspheres of volume fraction from about 6% to 66%.

Relatively strong peak of reflectance at the wavelength 4.5 lm was observed. This peak is explained in terms of theoretical model based on Mie theory calculations for single microspheres and modified two-flux approximation proposed recently by the authors. The reflectance of the composite material in the important range from 8.5 to 13.5 lm is determined mainly by rough surface layer of microspheres and it does not described by the model for semi-transparent media. The conditions of a considerable decrease in radiative heat losses from the buildings due to paint coatings containing hollow glass microspheres are discussed.

This article comes from researchgate edit released

Hollow glass microspheres with through-holes at micron level were fabricated by etching them using diluted 1% hydrofluoric acid (HF) solution in a specially designed reaction system.

In this study, the function of each component in the system was carefully investigated and improved to realise the controllable etching process. Various parameters were investigated to explore the optimal etching condition. Highest gross yield of about 85% and effective yield of about 50% were obtained at the optimised etching condition. A separating method was proposed to separate the etched hollow glass microspheres with different hole sizes with the help of reduced pressure.

After separation, hollow glass microspheres with hole size at sub-micron level, less than 10 µm, and bigger than 10 µm, were achieved. The well-etched hollow glass microspheres can be used as universal containers to store both reactive and inactive chemicals for applications in self-healing materials, biochemical engineering, and energy industry.

This article comes from ncbi edit released