Hollow glass spheres

G. H. Medley, Jr., J. E. Hasten, R. L. Montgomery, I. D. Martindale, and J. R. Duda. Field application of lightweight, hollow-glass-sphere drilling fluid, y Petrol Technol, 49(11) 1209-1211, November 1997. 

G. H. Medley, Jr., W. C. Maurer, and A. Y. Garkasi. Use of hollow glass spheres for underbalanced drilhng fluids. In Proceedings Volume, pages 511-520. Annu SPE Tech Conf (Dahas, TX, 10/22-10/25), 1995. 

IT. Filling Hollow Glass Spheres with Complex Hydrides... 

Formation of Porous Wall Hollow Glass Spheres... 

Figure 2 Scanning Electron Microscopy of hollow glass spheres a) Before acid leaching and b) After acid leaching...

Figure 4 Interior image of a cracked hollow glass sphere. Presence of a) bumpy structures and b) Needle shaped bundled structures...

Figure 5 Elemental mapping of the interior of a cracked hollow glass sphere following filling with sodium alanate...

Polymers such as polyethylene, which do not have polar groups, are excellent insulators of heat and electricity. The thermal insulating properties may be improved by foaming or by the incorporation of hollow glass spheres (syntactic foams). A low-density polyethylene foam will have a thermal conductivity in the order of 0.3 BTU/ft2 h F in. 

The Dow Chemical Company High Pressure Explosive Compositions and Method Using Hollow Glass Spheres... 

Recently, Kinra and Ker 137) published data of the shear modulus of syntactic foams consisting of hollow glass spheres in a poly(methyl methacrylate) matrix. The glass spheres had a mean radius of 45 pm and a wall thickness of 1.2 pm. Reliable values are known for the shear modulus of the polymer G0, the shear modulus of glass Gs, and Poisson s ratio of the polymer G0 = 1120 MPa, Gs = 2800 MPa, and v0 = 0.35. Using these values, the upper curve 1 of Fig. 24 was calculated by Nielsen for the modulus of the foam as a function of the volume fraction of hollow spheres. These calculated values are, however, too high compared with the experimental values reported by Kinra and Ker. 

A mixture of microspheres and the plastic can be formulated into a moldable mass that can then be shaped or pressed into cavities and molds much as molding sand and clay. The properties of the finished hardened or cured mass can then be tailored by a suitable plastic formulation. A mixture of TS polyester plastic and small hollow glass spheres, for example, can create synthetic wood. 

A second method for creating controlled nuclear fusion makes use of a laser beam or a beam of electrons or atoms. In this approach, hydrogen isotopes are suspended at the middle of the machine in tiny hollow glass spheres known as microballoons. The microballoons are then bombarded by the laser, electron, or atomic beam... 

Chemical composition variable composition silver coatings in Conduct-O-Fil solid glass spheres and fibers -4-16 wt%, 30% on hollow glass spheres, 65 wt% on mica flakes, 8-19 wt% on copper flakes, 24 wt% on nickel granules, 20 wt% on aluminum particles, nickel coating on Compmat carbon fiber is 24 wt%... 

Dry bulk resistivity, O-cm 0.005-0.008 (silver-coated products of PQ), 0.0017 (silver coated solid and hollow glass spheres - Conduct-O-Fil), 0.004 (silver coated glass fiber - Conduct-O-Fil), 0.0005-0.0006 (silver coated copper powder - Conduct-O-Fil), 0.0012 (silver coated copper flake - Conduct-O-Fil), 0.0007 (silver coated aluminum sphere - Conduct-O-Fil), 0.003 (silver coated inorganic flake - Conduct-O-Fil), 0.006 (silver coated nickel granules - Conduct -O-Fil), 0.0000016 - pure silver... 

AgCLAD TW and Filament 32 - a thick-walled spheres and fiber coated with silver, respectively Metahte SG, CG, SF-20 - light hollow glass spheres coated with silver Toho Rayon Co., Ltd, Tokyo, Japan... 

Asbestos, either powdered or in fiber form, imparts heat resistance aluminum trihydrate and talcum act as flame retarders mica gives excellent electrical properties and aluminum powder improves heat transfer. Powdered minerals such as silica or china clay are often used to Improve water resistance. One novel area is the use of hollow glass spheres in rigid polyurethane foam, known as "diafoam," to achieve 30-70% higher flexural and compression moduli. This foam is used as "structural foam" in furniture. 

Sphericet [Potters Industries] Hollow glass spheres filler for plastic conq>., molded parts yields weight reduction for finished pam. 

Another area of interest is microballoons for inertial confinement fusion (15). In this application dried gel fragments filled with a blowing agent can be dropped through a furnace to produce hollow glass spheres with high uniformity in wall thickness and sizes from 20 to 1500 microns in diameter. 

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