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POLYDIMETHYLSILOXANE Prepared at the 37th JECFA (1990), published in FNP 52 (1992) superseding specifications prepared at the 29th JECFA (1985), published in FNP 34 (1986). Metals and arsenic specifications revised at the 61st JECFA (2003). An ADI of 0-1.5 mg/kg bw was established at the 23rd JECFA (1979) | |
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SYNONYMS |
Poly(dimethylsiloxane), dimethylpolysiloxane, dimethylsilicone fluid, dimethylsilicone oil; INS No. 900 |
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DEFINITION |
Consists of fully methylated linear siloxane polymers containing repeating units of the formula (CH3)2SiO, with trimethylsiloxy end-blocking units of the formula (CH3)3SiO- The article of commerce used as an antifoaming agent can be further specified as to total silicon |
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Chemical names |
Simethicone (CAS name) |
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C.A.S. number |
8050-81-5 |
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Formula weight |
6,800 to 30,000 (average and approximate) |
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Assay |
Silicon content not less than 37.3% and not more than 38.5% of the total |
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DEION |
Clear, colourless, viscous liquid. Polydimethylsiloxane is frequently used in commerce as such, as a liquid containing 4-5% silica gel, and as an aqueous emulsion formulation containing, in addition to silica gel, emulsifiers and preservatives. The pure substance described here can be isolated by centrifuging from the silica gel-containing liquid at about 20,000 rpm. |
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FUNCTIONAL USES |
Antifoaming agent, anticaking agent |
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CHARACTERISTICS | |
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IDENTIFICATION | |
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Solubility (Vol. 4) |
Insoluble in water and in ethanol; soluble in carbon tetrachloride, benzene, chloroform, diethyl ether, toluene and other organic solvents |
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Specific gravity (Vol. 4) |
d (25, 25): 0.964 - 0.977 |
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Refractive index (Vol. 4) |
n (25, D): 1.400 - 1.405 |
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Infrared absorption |
The infrared spectrum of the sample corresponds with the reference infrared spectrum below. Prepare two solutions containing: (1) 10% of sample in carbon tetrachloride and (2) 2% of sample in carbon disulfide. Obtain the infrared spectrum for the sample using the carbon disulfide solution (2) from 1300 to 650 cm-1. The solvent in the reference cell is also changed at the appropriate wave numbers to correspond to the sample solution. |
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PURITY | |
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Loss on drying (Vol. 4) |
Not more than 0.5% (150o, 4 h) |
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Viscosity |
100 - 1500 cSt at 25o See deion under TESTS |
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Lead (Vol. 4) |
Not more than 1 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, "Instrumental Methods." |
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TESTS | |
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PURITY TESTS | |
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Viscosity |
Apparatus: The Ubbelohde suspended level viscometer, shown in the accompanying diagram, is preferred for the determination of the viscosity. |
| Identification | ||
| Name | Poly(dimethylsiloxane) | |
| Synonyms | Dimethylpolysiloxane; Dimethicone; Simethicone | |
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| Molecular Structure |  | |
| Molecular Formula | (C2H6OSi)n | |
| CAS Registry Number | 9016-00-6 | |
| Properties | ||
| Density | 0.971 | |
| Water solubility | INSOLUBLE | |
| Safety Data | ||
| Safety Deion | S24/25 Details | |
| List of Suppliers | ||
| The Complete List of Suppliers for Poly(dimethylsiloxane) | ||
