Synthetic mica

Additives used in final products Fillers calcium carbonate, carbon black, glass fiber, graphene oxide, graphite, magnesium carbonate, mica, synthetic graphite, wollastonite ... 

MICA. Synthetic mica has recently been put into commercial production and is available in various powdered forms in organically bonded paper sheets in a three-dimensional, hot-pressed, machinable synthetic mica ceramic and in sheet form of limited area. Synthetic mica has unusually high thermal... 

This includes inorganic materials such as mica, glass fibre and asbestos etc., impregnated or glued together with varnishes or compositions comprising ordinary organic substances for heat resistance such as oil-modified synthetic resins, bitumen, shellac and Bakelite. 

Although development work on shellac in blends with other synthetic resins has been carried out over a period of time, the only current use in the plastics industry is in the manufacture of electrical insulators. At one time electrical insulators and like equipment were fabricated from mica but with increase in both the size and quantity of such equipment shellac was introduced as a binder for mica flake. For commutator work the amount of shellac used is only 3-5% of the mica but in hot moulding Micanite for V-rings, transformer rings etc., more than 10% may be used. The structures after assembly are pressed and cured, typically for two hours at 150-160°C under pressure. 

Polyimide-clay nanocomposites constitute another example of the synthesis of nanocomposite from polymer solution [70-76]. Polyimide-clay nanocomposite films were produced via polymerization of 4,4 -diaminodiphenyl ether and pyromellitic dianhydride in dimethylacetamide (DMAC) solvent, followed by mixing of the poly(amic acid) solution with organoclay dispersed in DMAC. Synthetic mica and MMT produced primarily exfoliated nanocomposites, while saponite and hectorite led to only monolayer intercalation in the clay galleries [71]. Dramatic improvements in barrier properties, thermal stability, and modulus were observed for these nanocomposites. Polyimide-clay nanocomposites containing only a small fraction of clay exhibited a several-fold reduction in the... 

FIG. 13 Reduction of the relative permeability coefficient is dependent on the clay platelet aspect ratio in the system of polyimide-clay hybrid with water vapor as the permeate. Each hybrid contains 2 wt% clay. The aspect ratios for hectorite, saponite, montmorillonite, and synthetic mica are 46, 165, 218, and 1230, respectively. (From Ref. 71.)... 

Blencoe J. G. (1977). Molal volumes of synthetic paragonite-muscovite micas. Amer. Mineral, 62 1200-1215. 

Micas are also composed of Si-0 tetrahedra. The anionic charge on the silicate sheet is the result of the replacement of silicon by aluminum. Cations such as potassium are interspaced between these negatively charged sheets. Some micas are used in construction and electrical engineering applications. Synthetic mica is manufactured on a large scale for industrial consumption in coatings, as fillers, etc. Micas are one of the many layered Si-0-intense materials found in nature. 

Figure 5. Typical X-ray diffraction traces of the (001) reflection for mica and mica-illite minerals. Assymmetry is shown towards large values. A - natural 2M muscovite B = natural illite (IMd) C - synthetic illite (lMd), 75% mica, 25% prophyllite composition D = synthetic 1M muscovite E - natural 1M glauconite F = synthetic 1M celadonite mica.

Natural mica compositions of the dioctahedral, potassic types have been discussed by Velde (1965b) in connection with the solid solution between muscovite and the different celadonite mica molecules. It was shown that both natural and synthetic micas formed two distinct compositional and genetic groups. The important point made in the discussion is the definition of the term mica. The most restrictive criteria as was mentioned before is the necessity for the mineral in question to have a net charge (the sum of octahedral and tetrahedral electrostatic... 

The presence of an organophilic clay increases the catalyst activity (10). Suitable clays include montmorillonite, hectorite, mica, etc. For example, Lucentite is a trioctylmonomethylammonium salt-treated synthetic hectorite. The clays are modified with quaternary ammonium compounds. The clays are heat treated prior to their use in the polymerization process. Further, the incorporated clay can improve the performance of the UHMWPE or function as filler. 

Alkylation of toluene with methanol, a process of practical importance, was investigated over several acidic clay catalysts.98 Cation-exchanged synthetic saponites201 and fluor-terasilicic mica modified by La3+ ions202 were found to exhibit increased para selectivity compared with H-ZSM-5. 

The dominant class of nacreous pigments is based on platelets of natural mica coated with thin films of transparent metal oxides (see Fig. 73). Mica minerals are sheet silicates (laminar). Nacreous pigments are usually based on transparent muscovite [9941-63-5] but some are based on natural or synthetic phlogopite [110710-26-4]. Although muscovite occurs worldwide, few deposits are suitable for pigments it is biologically inert and approved for use as a filler and colorant [5.220], [5.221],... 

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