Talc powder

Control shrinkage after moulding. Any filler will decrease shrinkage most commonly used are silica, clay, calcium carbonate, alumina, talc, powdered metals and lithium aluminium silicate. 

The first aerosol experiments in this series utilizing quantitative techniques were performed by the writer in 1954. Two types of delivery were employed (a) powdered LSD diluted with talc, administered by means of a simple inertia device (Fig. la) (b) aqueous solutions of LSD administered intranasally by means of the nebulizer illustrated in Fig. lb. When a talc-LSD powder was administered intranasally, very severe reactions occurred rapidly. With a maximum dose of 256 meg delivered intranasally in the form of LSD-talc powder, subject J.M. had a most severe reaction, withdrawing to one part of my home in which the experiment took place and refusing to cooperate in his usual fashion. The data on Subject J.M. in this experiment are available. In order to study liquid aerosols, aqueous solutions of LSD-25 were administered intranasally to Subject J.M. The questionnaire was again used to estimate the severity of the reaction. The following technique of comparison was employed. 

Boron finds uses in the cosmetics industry (talc powder), in soaps and adhesives, and as an environmentally safe insecticide. 

A study was made of nucleation in PE foams produced in a counter-rotating extruder using talc powders and masterbatches as nucleating agents and CFG and HCFC blowing agents. The results indicated the importance of shear force in nucleation, as proposed in the lump cavity nucleation model and demonstrated by melt temperature effects observed in these experiments. It was shown that shear enhancement via lump break-up was not a vital mechanism in nucleation. 6 refs. 

Iran. The grain is taken orally for intestinal inflammation and administered rectally for diarrhea. The grain flour is used externally to reduce topical inflammation, to remove rash and erythema, and to treat genital irritation in children resulting from contact with urine, and it is mixed with talc powder to prevent dryness of the skin . ... 

In the case of adsorption from solution, the surfactant layers are in equilibrium with the solution and will de-sorb on dilution. However, it would be very useful to produce adsorbed layers in both air and water, which will remain adsorbed. This can be achieved using the Langmuir-Blodgett deposition technique. The technique is based on the observation that if a surfactant, which is insoluble in water, is dissolved in a volatile, non-aqueous solvent and then spread on water, an insoluble monolayer of orientated surfactant molecules will remain at the air/solution interface. The effect of the spreading surfactant and its surface film pressure can be dramatically demonstrated by spreading hydrophobic talc powder on a clean water surface and then placing a... 

The surface of the subsolution was cleaned by first dusting it with Talc powder and then sweeping the surface by moving a Teflon slide from one side of the trough to the other. The Talc powder along with the impurities (if any) were then removed using... 

Finally, gap spacing and pressurization are truly the heart of the problem. The desirable conditions are fineness of the spacer material, its water repellency, and the degree to which it maintains the air pressure excess over the entire membrane surface. Drifilmed talc powder, Xerox powder, and silicone-coated pumice powder have all been used with success with relatively low pressure differentials across the sea water capillary membrane. 

Tremolite-actinolite is present in or around some deposits of chrysotile asbestos. However, levels of amphibole asbestos in commercial chrysotile were not reported. Tremolite is a contaminant in talc from New York and California, but the extent and fibrosity of the tremolite is unclear (DOT 1980 Wagner et al. 1982c American Thoracic Society 1990). The tremolite in some talc Ifom Califomia has been described as flake-like and that from New York as having fine fibers (Wagner et al. 1982a). Some tremolite in the chrysotile Ifom Quebec has been described as having coarse fibers. A British survey of talc powders used for various purposes identified 3 out of 24 samples as containing tremolite. Ten of 20 samples of cosmetic talc purchased in New York City between 1971 and 1975 contained 1-14% (w/w) of fibrous tremolite and... 

Results of a survey of asbestos fibers in consumer cosmetic talc powders from Italian and international markets using electron microscopy, electron diffraction, and energy dispersive x-ray analysis showed that asbestos was detected in 6 of 14 talc samples from the European Pharmacopeia (Paoletti et al. 1984). Chrysotile was identified in 3 samples, 2 samples contained tremolite asbestos and anthophyllite asbestos, and 1 sample contained chrysotile and tremolite asbestos. The authors noted that, in all talc powders analyzed, fibrous talc particles frequently were present that were morphologically similar to amphibole asbestos fibers. Counting fibers as particles with aspect ratio >3 1 and width < 3 m, the percentages of particles that were asbestos fibers ranged from <0.03% to 0.13% for 4 samples, and were 18% to 22% for the other 2 samples. Paoletti et al. (1984) noted that the European Pharmacopeia, at that time, had not established analytical quality control of asbestos contamination. 

Seller R, Caldini O, Orzalesi G, et al. Preservation of cosmetic products protection of the talc powders. Boul Chim Farm 1974 113(Dec) 617-627. 

Inhalation, dermal, perhaps some oral, and publications of uptake application to the genital area (uptake via the vagina). Potential occupational exposures include cosmetic workers, paint makers, paper makers, pottery makers, rubber cable coaters, rubber tire makers, talc millers, talc miners, and talc powder makers. Consumer exposures involve various talc-containing products. 

The effect of the adsorbed surfactant-polymer complex on the rheology of the air-aqueous solution interface is easily detected by the talc particle test (Regis-mond, 1997). A small quantity of calcined talc powder is sprinkled on the surface of the aqueous solution in a 10-cm Petri dish. A gentle current of air is directed tangentially to the talc particles for 1-2 s and then removed. The observed movement is noted in the following categories fluid (F), viscous (V), gel (G) (= almost no flow), solid (S) (= no flow), and viscoelastic (VE) (= net movement, with some recovery upon removal of air current). 

Sclerosol aerosol 4 g talc, Sterile talc powder 5 g talc)... 

Shrinkage Any filler will decrease shrinkage the most commonly-used fillers are silica, clay, calcium carbonate, alumina talc, powdered metals, and lithium aluminum silicate. Low-shrink or low-profile additives are used in TS systems such as SMCs and BMCs to minimize shrinkage during and after molding, and improve the surface appearance of a molding. 

Because talc powder is so fine-grained you should be careful to not directly inhale it into your lungs. It can become trapped and cause respiratory problems. 

The spreading of surfactants forced the water to flow away from the initial location of th drop thus creating a depression where only a thin film of liquid subsisted. The periphery of thi depression, i.e. the liquid front had a sharp increase in thickness. The water layer wa horizontal and the drop was carefully placed, hence, there was no preferred direction, and th edge was circular but some modulation could appear in the experiment after a few seconds Note that the surfactant occupied more surface area of the film than the depressed zone sine the talc powder is pushed ahead of it. The dependence on time of the radius of the surfactan patch is given in Fig. 3 using log-log plot. 

The specimens are prepared by pouring the heated bitumen into ductility brass moulds assembled on a brass or metallic plate. Before pouring the bitumen, the surface of the metallic plate is coated with a release agent (typically a mixture of glycerin and talc powder). This prevents specimen from sticking to the plate and to the detachable middle part of the mould (side pieces), after allowing the filled mould to cool to room temperature. 

If talc powder is gently placed on a liquid surface, gently blowing on the surface causes the particles to move relatively freely. If the surface is covered with a low density monolayer film movement becomes more restricted, but relatively free movement is still evident. If the film pressure is increased (i.e., more molecules per unit area of surface), at some point the particles become fixed in place—the surface viscosity has increased substantially and the film behaves as if it is in a condensed state (see text below). 

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