Glass boron

Economic Aspects and Uses. The principal producers in the United States are U.S. Borax and Chemical Corp., North American Chemicals Co., and American Borate Corp. Their combined aimual capacity in 1989 was reported to be 735,000 metric tons of equivalent boron oxide [1303-86-2], B2O2 (20). Of this toimage, 50% is exported. About 30% of boron compounds are used in glass fiber insulation. Another 30% is used in other type fibers and borosihcate glasses. Boron is also used in soaps and detergents, fire retardants, and agriculture (see Boron compounds). 

Furuno, T., Uehara, T. and Jodai, S. (1993). Combinations of wood and silicate III. Some properties of wood-mineral composites using water-glass-boron compound system. Mokuzai Gakkaishi, 39(5), 561-570. 

Composite Structures. Polylmides have been utilized for the fabrication of composites of quartz, glass, boron, graphite and... 

Property Test method Unit Borosilicate E-glass Boron-free E-glass... 

Strength fibers can be reduced by hybridization, i.e., by designing composites reinforced with mixed HS-glass/carbon, HS-glass/aramid, or HS-glass/boron fibers. 

M.P. Hanson, Glass-, Boron-, and Graphite-Filament-Wound Resin Composites and Liners for Cryogenic Pressure Vessels, NASA... 

Boric acid is a weak acid used in eye washes and to clean glass. Boron is also a natural insecticide, since many insects caimot metabolize the boron molecule. Boric acid when mixed with equal parts white flour and powdered sugar makes a tempting insect bait for cockroaches. It causes internal blockage and death, while being safe for animals and children. 

Important fiber materials are surface-treated glass, boron, graphite (carbon), and aromatic polyaramides (eg, DuPont s Kevlar). In most composites the reinforcement constitutes ca 65% of the final mass. Orientation of the fibers is important in establishing the properties of the laminate. Unidirectional, bidirectional, and random orientations are possible. The characteristics of the cured resin system are extremely important since it must transmit the applied stresses to each fiber. A critical region in a composite is the resin-fiber interface. The adhesive properties of epoxy resins make them especially suited for composite applications. 

A third way to toughen plastics is to add fibers, to make composite materials (3). Fibers in use today include glass, boron, graphite, or other polymers. These may be chopped or added as continuous filaments. With continuous filaments, the fibers carry most of the mechanical load, while the polymeric matrix serves to transfer stresses to the load-bearing fibers and to protect them against damage (31-34). Thus, a controlled amount of adhesion between the fibers and the matrix is required. 

Boron was known to the ancients in the form of borax, which was used for various types of glass. Boron is almost always found directly bound to oxygen and is difficult to prepare in pure form. In 1808 the ebullient chemist Sir Humphry Davy, whom we encountered as the discoverer of potassium and sodium (p. 324) as well as magnesium, calcium, strontium, and barium (p. 355), was just barely beaten (by 9 days) to the discovery of boron by the French chemists Joseph Louis Gay-Lussac and Louis Jacques Thenard. Yes, this is the same Gay-Lussac who proved (in 1802) that the volume of a gas is directly proportional to the temperature. (Jacques Charles, a French physicist, actually formulated this relationship some 15 years earlier, but... 

A list of materials regarded as high-performance polymers (Table 17.10) overlaps the list of Table 17.9 to some extent, but also includes thermosets such as epoxy, phenolic, and silicone molding resins. As with most molded plastics, high-tanperature performance is enhanced by reinforcement with glass, boron, or carbon or aramid fibers. The thermosets are seldom used without reinforcement. Several are inclnded in Figures 17.6 and 17.7. 

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