Solid and Hollow Glass Spheres

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... 

Table 21.3 Comparison of A-glass-based solid and hollow glass spheres.

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%... 

Tensile, flexural, and impact properties of compounds filled with hollow glass spheres are similar to those with solid spheres and research shows that there are significant benefits in properties when organosilane coupling agents are used. 

Microsphere Insulation. Good thermal-insulation performance has also been achieved by using packed, hollow glass spheres, typically of a size ranging from 15 to 150/xm in diameter and coated on the exterior with a film of low emittance material such as aluminum. These hollow spheres, which generally have a wall thickness of 0.5-2.0 m, substantially increase the conduction thermal resistance but markedly reduce the heat capacity and the mass relative to solid particles. Further, hollow microspheres offer a lightweight and low heat capacity alternative to MLI. A comparison of these two insulations is presented in Table 7.4. 

Names nickel coated carbon fiber, steel fiber, powder, silver coated hollow and solid glass spheres, silver coated mica, silver coated fiber... 

Delzant M, A Contribution Towards Studying the Behavior of Composites Containing Microperl Solid and Microcel Hollow Glass Microspheres or a Combination of Fibers and Spheres as Fillers. Abrasivos Y Maquinaria, S A, Barcelona, Spain. 

Also available are whisker reinforcements with exceptional high performances (Chapter 2). Also used are non-fibrous materials, such as steel wire (Table 1.6), and surface-treated mineral fillers that include mica platelets, talc, fibrous and finely divided minerals, glass flakes, and hollow and/or solid glass micro spheres. Lightweight expanded materials, such as sheets of reinforced foam or honeycomb, are used as cores in sandwich structures (Chapter 7). 

Examples of inert or extender fillers include china clay (kaolin), talc, and calcium carbonate. Calcinm carbonate is an important filler, with a particle size of about 1 pm. It is a natural product from sedimentary rocks and is separated into chalk, limestone, and marble. In some cases, the calcium carbonate may be treated to improve interaction with the thermoplastic. Glass spheres are also used as thermoplastic fillers. They may be either solid or hollow, depending on the particular application. Talc is a filler with a lamellar particle shape. It is a namral, hydrated magnesium silicate with good slip properties. Kaolin and mica are also natural materials with lamellar structures. Other fillers include woUastonite, silica, barium sulfate, and metal powders. Carbon black is used as a filler primarily in the rnbber industry, but it also finds application in thermoplastics for conductivity, for UV protection, and as a pigment. Fillers in fiber form are often used in thermoplastics. Types of fibers inclnde cotton, wood flour, fiberglass, and carbon. Table 1.3 shows the fillers and their forms. An overview of some typical fillers and their effect on properties is shown in Table 1.4. Considerable research interest exists for the incorporation of nanoscale fillers into polymers. This aspect will be discussed in later chapters. 

Glass and ceramic spheres are used extensively in thermoplastics and thermosets. They may be solid or hollow with densities varying from 2.5 to 0.1 g/cm. The spheres... 

Calcium carbonate is an important filler with a particle size of about 1 p,m. It is a natural product from sedimentary rocks and is separated into chalk, limestone, and marble. In some cases the calcium carbonate may be treated to improve the bonding with the thermoplastic. Glass spheres are also used as thermoplastic fillers. They may be either solid or hollow, depending on the particular application. Talc is an important filler with a lamellar particle shape. It is a natural hydrated magnesium silicate with good slip properties. Kaolin and mica are also natural materials with lamellar stracture. Carbon black is used as a filler primarily in the rubber industry. 

Glass beads Small solid or hollow sphere of glass. Range 1-53 p.m diameter, bulk densities hollow = 0.15-0.38 g/cm, solid = 1.55 g/cm. Usually treated with cross-linking additives Used as a filler, flow aid, or weight reduction medium in casting, lamination, and press molding. 

Glass microspheres due to their spherical nature can be easily moulded as polymer can flow with ease around spheres. Also impart toughness. Have a typical diameter range of 20-200 jim, and can be either solid or hollow. 

Fig. 5.13 Comparison of calculation results and experiments with regard to median drop diameter for spherical glass beads and hollow spheres D = 80, Re = 28, We = 4.7, Fr = 49, Pg/pi = 0.001, and va = 0 m/s. Solid lower lines are the results from the temporal stability analysis and dashed upper lines are those from the spatial stabihty analysis, (a) Breakup length from the experiment, Ro = 0.25 and pjpi = 2.1. (b) Breakup length from Eq. (5.53), Fg = 0 and = 0.1...

Syntactic foam contains an orderly arrangement of hollow sphere fillers. They are usually glass microspheres approximately 100 microns (4 mils) in diameter, provide strong, impervious supports for otherwise weak, irregular voids. As a result, syntactic foam has attracted considerable attention both as a convenient and relatively lightweight buoyancy material and as a porous solid with excellent shock attenuating characteristics. The latter characteristic is achieved... 

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