Inorganic fibers mechanical

In this book we define inorganic fibers in a general sense as small elongate solid objects composed of any compound or element usually nonbio-logic in origin and often exhibiting distinctive physical, especially mechanical, properties. Inorganic fibers can occur naturally, that is, as mineral fibers or can be produced synthetically. 

Inorganic fibers can also be produced from substances that do not form polymers. Under special conditions, virtually any compound can grow as a fibrous solid. These conditions occasionally exist in nature, but today many inorganic fibers are custom-crafted. A compound synthesized in fibrous form usually possesses additional and desirable mechanical properties over the compound in any other form. 

Hemp rope, once widely used, has largely been replaced by iiylon cord. The flexibility and mechanical strength of hemp, a nettle plant fiber, also characterize nylon synthetic and several other inorganic fibers in common use. 

Inorganic fibers Felt Pure felt To 2200°F Excellent heat resistance, poor mechanical properties. Resilient, compressible and strong, but not impermeable. Resists medium-strength mineral acids and dilute mineral solutions if not intermittently dried. Resists oils, greases, waxes, most solvents. Damaged by alkalies. 

In extrusion, in addition to the nature and the properties of the materials used to make the moldable mixture, the additives used, the pH, the water content, and the force used in extrusion are also of importance with respect to the properties of the monolith products [31]. The additives applied in extrusion are, e.g., celluloses, CaCl2, ethylene, glycols, diethylene glycols, alcohols, wax, paraffin, acids [13,16,24,30], and heat-resistant inorganic fibers [24]. Besides water, other solvents can also be used, such as ketones, alcohols, and ethers [15,16]. The use of additives may lead to improved properties of the monoliths, such as the production of microcracks that enhance the resistance to thermal shock [4,12], better porosity and adsorbability [15,16], and enhanced mechanical strength or a low thermal expansion [24]. 

By far the most important application fields for inorganic fibers are the insulation and reinforcing sectors. Fibers are also used as fillers and as filter materials. As with other materials, functional properties such as electrical, optical or magnetic properties are becoming increasingly important for fibers, in addition to mechanical and electrical properties. 

Using the classical resol chemistry, Asai and coworkers patented new molded materials.Added to the resol phenolic resin are inorganic fiber, a silica powder, and a rubber component. The prepared phenolic resin composition was noted to have excellent resistance to abrasive wear and to heat shock, as well as excellent mechanical strength. As such, this material is very suitable for the fabrication of engine parts such as pulleys. These pulleys are currently fabricated from heavier and more expensive materials. 

Table 11.3 Mechanical properties of selected organic and inorganic fibers.

Oxidation. Hydrogen peroxide is a strong oxidant. Most of its uses and those of its derivatives depend on this property. Hydrogen peroxide oxidizes a wide variety of organic and inorganic compounds, ranging from iodide ions to the various color bodies of unknown stmcture in ceUulosic fibers. The rate of these reactions may be quite slow or so fast that the reaction occurs on a reactive shock wave. The mechanisms of these reactions are varied and dependent on the reductive substrate, the reaction environment, and catalysis. Specific reactions are discussed in a number of general and other references (4,5,32—35). 

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