Phlogopite properties

Muscovite mica formed as a primary mineral in pegmatites and granodiorite differs in physical properties compared to muscovite mica formed by secondary alteration (mica schist) (Table 2). The main differences are in flexibiUty and abiUty to be delaminated. Primary muscovite is not as brittle and delaminates much easier than muscovite formed as a secondary mineral. Mineralogical properties of the principal natural micas are shown in Table 3. The make-up of muscovite, phlogopite, and biotite are as follows ... 

Property Muscovite Phlogopite Biotite Synthetic fluorophlogopite... 

PHYSICAL PROPERTIES (M) - muscovite mica, (P) - phlogopite mica most data in this table courtesy of Polar Minerals, Mt. Vernon, IN, USA ... 

The original studies of optical spectra of micas arose from an interest in the variable colors of muscovite and phlogopite (e.g., Hall 1941), which formed the basis for commercial classification of their electrical properties. However, subsequent research has used optical spectroscopy to delve into the assignment of Fe and IVCT bands, as well as the issue of the site occupancy of Fe ... 

Circone S, Navrotsky A (1992) Substitution of " A1 in phlogopite high-temperature solution calorimetry, heat capacities, and thermodynamic properties of the phlogopite-eastonite join. Am Mineral 77 1199-1205... 

CHEMICAL PROPERTIES noncombustible solid generally resistant to chemical attack exceptions are muscovite (which decomposes in hydrofluoric acid) and phlogopite (which is mildly attacked by hydrochloric acid and decomposes in hot sulfuric acid) it is dielectric FP (NA) LFL/UFL (NA) AT (NA) pH (neutral) IR (1.58). 

Muscovite is the principal mica used because of its abundance and superior electrical properties. Phlogopite... 

Mica products are also very stable at high temperatures. Thermogravimetric analysis shows that both muscovite and phlogopite mica are thermally stable to over 450°C, which is far above the processing temperatures for polyolefin composites. Table 14.3 lists some of the more important physical properties of mica. 

A comparison of the properties of surface-treated phlogopite mica with talc, calcium carbonate, glass, and the unfilled resin is given in a technical bulletin produced by Marietta Resources International, Ltd. (10). Table 14.7 shows that 40 wt% mica-filled polypropylene (Profax 6523) had a higher flexural modulus than 30 wt% glass fiber-filled polypropylene (1.04 X 10 psi versus 0.93 X 10 psi). The compound filled with 40 wt% surface-modified mica also had higher Izod impact than the 40 wt% talc-filled compound (0.65 versus 0.45 ft-lb/in). 

Naturally occurring micas have a variety of chemical compositions and morphologies. Three major types are commercially available for use in polymers wollastonite, muscovite, and phlogopite. Mica particles are sometimes fiber shaped, but more commonly platelet or flake shaped. Their aspect ratio (width-to-thickness ratio) plays an important part in the reinforcement properties. 

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