Novel thermal insulation material consisting of a frame work of hollow glass microspheres and embedded silica aerogel was prepared by allowing silica sol to penetrate into HGM ceramics, followed by drying under ambient pressure. hollow glass microspheres porous ceramics were obtained after sintering of closed packed HGMs together. Properties such as density, porosity, compressive strength, thermal conductivity (λ), and microstructure of each specimen prepared at different temperatures were systematically studied.

Results showed that hollow glass microspheres ceramics had lower density ranging from 0.136 to 0.701 g/cm3. The density, compressive strength, and λ of hollow glass microspheres ceramic increased with increase in sintering temperature and true density of hollow glass microspheres. After filling hollow glass microspheres ceramic with silica aerogel, thermal conductivity was reduced by about 27%. Moreover, the introducing of aerogel changed the mode of thermal conduction of the composite by reducing heat transfer of air between hollow glass microspheres. The composite showed super-hydrophobicity (contact angle >150°) due to the presence of organic methyl groups.

Silica aerogel/hollow glass microspheres ceramics with low density and low thermal conductivity prepared by embedding of silica aerogel into hollow glass microspheres ceramic, not only overcame the disadvantage of large-size aerogel materials during fabrication, but also solved the problem of high water absorption of inorganic materials.

This article comes from x-mol edit released

Hollow glass microspheres made of glass, polymer, or crystal material have been largely used in many application areas, extending from paints to lubricants, to cosmetics, biomedicine, optics and photonics, just to mention a few.

Here the focus is on the applications of hollow glass microspheres in the field of energy, namely covering issues related to their use in solar cells, in hydrogen storage, in nuclear fusion, but also as high-temperature insulators or proppants for shale oil and gas recovery.

An overview is provided of the fabrication techniques of bulk and hollow glass microspheres, as well as of the excellent results made possible by the peculiar properties of hollow glass microspheres. Considerations about their commercial relevance are also added.

Porous hollow glass microspheres have many uses, including porosity enhancers for lead-acid batteries. A fast, facile and high yield synthetic method for fabricating porous hollow glass microspheres with diameters around 45–55 μm is demonstrated. The process involves shaking commercially available hollow glass microspheres in dilute hydrofluoric acid for 20 min. This process yielded two pore morphologies by using different commercially available starting materials; Yields were 33% and 40%, respectively. The simplicity of the reported fabrication technique has the potential to be scaled up for large scale production.

Applications:

  • Porous hollow glass microspheres are synthesized for use as battery additives.
  • A simple fabrication method with commercial hollow glass microsphere precursors.
  • Sponge-like submicron pores or straight through micron pores created.
  • Yields were 33–40%.

This article comes from sciencedirect edit released

Porous-wall hollow glass microspheres are a novel form of glass material consisting of a 10 to 100 micron-diameter hollow central cavity surrounded by a 1 micron-thick silica shell. A tortuous network of nanometer-scale channels completely penetrates the shell.

We show here that these channels promote size-dependent uptake and controlled release of biological molecules in the 3–8 nm range, including antibodies and a modified single-chain antibody variable fragment (scFv). In addition, a 6 nm (70 kDa) dextran can be used to gate the porous walls, facilitating controlled release of an internalized small interfering RNA.

Porous-wall hollow glass microspheres remained in place after mouse intratumoral injection, suggesting a possible application for the delivery of anti-cancer drugs. The combination of a hollow central cavity that can carry soluble therapeutic agents with mesoporous walls for controlled release is a unique characteristic that distinguishes porous-wall hollow glass microspheres from other glass materials for biomedical applications.

This article comes from ncbi edit released

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 hollow glass microspheres.

The results obtained were used to select a suitable less toxic and environmental friendly modification method based on the chemicals used.

This article comes from scirp edit released

Composites that simultaneously combine light weight with high electrical and low thermal conductivity are very desirable for aerospace, marine, and energy applications but are hard to achieve in practice. Now researchers think they may have the answer in the form of hollow glass microspheres covered with carbon nanofibers, which can be used as a filler for polymer composites.

Hollow glass microspheres are well-known additives for polymer composites because of their light weight and low thermal conductivity. But the lack of interaction between glass microspheres and the polymer matrix reduces the composite’s strength. Carbon nanotubes and fibers hold promise as fillers for polymer composites because of their electrical conductivity. To get just the right balance of properties, the researchers sought to bring together the best attributes of each of these fillers in one material.

By growing carbon nanofibers directly on the surface of hollow glass microspheres, we do not need complicated techniques to disperse the nanofibers in the matrix so we can mix them as a standard microfiller.

This article comes from materialstoday edit released

Plastisols are relatively stable fluid dispersions of finely divided plastic resin particles in a liquid plasticizer with a small amount of diluent (solvent).

Further additives are introduced to the plastisols, such as fillers, pigments, adhesion promoters, rheology auxiliaries (separation inhibitors), heat stabilizers, blowing agents, reactive (capable of cross-linking) additives, and water-absorbing substances (calcium oxide).

Hollow glass microsphere fillers are mainly used to reduce density while also providing viscosity control, sag, and impart thixotropy to the unfluxed plastisol solution increasing shelf life of low density seam sealers. Plastisol based automobile coatings and seam sealers must meet rigid standards set by various automobile manufacturing companies. A very important requirement for plastisol coatings is that they be lightweight.

As plastisol manufacturers strive for lighter and hence more fuel efficient vehicles, hollow glass microspheres has become a crucial part of the plastisol formulations as key raw material filler. Hollow glass microspheres in plastisols are described in detail in this chapter.

This article comes from sciencedirect edit released

Traditional Applications for Hollow Glass Microspheres

  • Low density fillers for composites with polymers and concrete
  • Thermally insulating paint
  • Thermally insulating tapes
  • Syntactic foams for submersibles
  • Targets for laser fusion systems (D/T filled)

Modern Applications for Hydrogen-Filled Hollow Glass Microspheres

  • Hydrogen storage
  • Hydrogen separation and purification
  • Radiation shielding for manned space flight

Summary

  • Hollow glass microspheres have many attractive features as a hydrogen storage medium
  • Optically-induced outgassing of hydrogen from glass is significantly faster than conventional heating
  • Current work seeks to demonstrate feasibility using hollow glass microspheres

This article comes from lehigh edit released

Hollow glass microspheres are available as commercial products in large quantities at cost of less than US$2 per kilogram, which would be expected to decrease with economies of scale.

The raw materials are relatively inexpensive, the production processes are well established, and the durability of the spheres is such that they can withstand a large number of filling/outgassing cycles. The materials can easily be recycled to produce new spheres to replace those broken during service.

As a result, hollow glass microspheres appear to be the cheapest of all current materials for the solid-state storage of hydrogen.

This article comes from sciencedirect edit released

The production of hollow glass microspheres is part of an ongoing research and development program started in 1974. And aimed at developing a method for mass producing glass fuel containers for use in inertial confinement fusion (ICF) experiments. Several previous reports have described the development of the liquiddroplet technique for the production of hollow glass microspheres.

In this paper, ive review previous data along with tie results from our more recent studies to present a detailed picture of the preparation method and properties of the hollow glass microspheres. The production of the high-quality hollow glass microspheres needed for laser fusion targets requires us to optimize a number of processing parameters.

In the past, we used a largely empirical approach to determine the proper operating conditions. Although this approach was successful, it was also time consuming and manpower intensive. To help guide and interpret our present experimental work, we have developed a simple, onedimensional (1-D) model to simulate the sphere formation process.

The model has been used to quantify the effects of several key process variables such as the column temperature profile, purge-^as composition, droplet size and composition, and glass film properties.

This article comes from osti edit released