Silicone grease

Source: Wikipedia, the free encyclopedia.

Silicone grease, sometimes called dielectric grease, is a waterproof

polytetrafluorethylene (PTFE).[1]
Greases formulated from silicone oils with silica thickener are sometimes referred to as silicone paste to distinguish them from silicone grease made with silicone oil and a soap thickener.

Applications

Industrial use

Silicone grease is commonly used for lubricating and preserving many types of rubber parts, such as

which?] factors. It functions well as a corrosion inhibitor
and lubricant on non-metal-metal contact areas.

Silicone grease is soluble in organic solvents such as

chlorinated hydrocarbons. It is insoluble in methanol, ethanol, and water.[2]

Thermal grease
often consists of a silicone-grease base, along with added thermally conductive fillers. It is used for heat-transfer abilities, rather than friction reduction.

Pure silicone grease is widely used by the plumbing industry in faucets and seals, as well as in dental equipment. This is because it is not an ingestion hazard[citation needed]. Electrical utilities use silicone grease to lubricate separable elbows on lines that must endure high temperatures. Silicone greases generally have an operating temperature range of approximately −40 to 200 °C (−40 to 392 °F) with some high-temperature versions extending this range slightly.[3]

Chemical laboratories

Silicone grease is widely used as a temporary sealant and a lubricant for interconnecting ground glass joints, as is typically used in laboratory glassware. Although silicones are normally assumed to be chemically inert, several historically significant compounds have resulted from unintended reactions with silicones.[4][5] The first salts of crown ethers (OSi(CH3)2)n (n = 6, 7) were produced by reactions of organolithium and organopotassium compounds with silicone greases[6] or the serendipitous reaction of stannanetriol with silicone grease to afford a cage-like compound having three Sn−O−Si−O−Sn linkages in the molecule.[7]

Lubrication of an apparatus with silicone grease may result in the reaction mixture being contaminated with the grease. The impurity may be carried through purification by

NMR spectroscopy, the methyl groups in polydimethylsiloxane display 1H and 13C chemical shifts similar to trimethylsilane (TMS), the reference compound for those forms of NMR spectroscopy. As with TMS, the signal is a singlet. In 1H NMR, silicone grease appears at a singlet at δ = 0.07 ppm in CDCl3, 0.09 in CD3CN, 0.29 in C6D6, and −0.06 ppm in (CD3)2SO. In 13C NMR, it appears at δ = 1.19 ppm in CDCl3 and 1.38 ppm in C6D6. Tables of impurities commonly found in NMR spectroscopy have been prepared, and such tables include silicone grease.[8]

Consumer products

Silicone-based lubricants are often used by consumers in applications where other common consumer lubricants, such as petroleum jelly, would damage certain products, such as latex rubber and gaskets on dry-suits. It can be used to lubricate fountain pen filling mechanisms[9] and threads. Another common use is to lubricate keyboard stabilizer wires to reduce rattle.[citation needed]

Electrics

Silicone greases are electrically

insulating and are often applied to electrical connectors, particularly those containing rubber gaskets, as a means of sealing and protecting the connector. In this context they are often referred to as dielectric grease.[10][11]

A common use of this type is in the high-voltage connection associated with gasoline-engine spark plugs, where grease is applied to the rubber boot of the plug wire to help it slide onto the ceramic insulator of the plug, to seal the rubber boot, and to prevent the rubber's adhesion to the ceramic. Such greases are formulated to withstand the high temperature generally associated with the areas in which spark plugs are located, and can be applied to contacts as well (because the contact pressure is sufficient to penetrate the grease film). Doing so on such high-pressure contact surfaces between different metals has the further advantage of sealing the contact area against electrolytes that might cause rapid deterioration of the metals by galvanic corrosion.[12]

Silicone grease can decompose to form an insulating layer at or next to switch contacts that experience

arcing, and contamination can cause the contacts to prematurely fail.[13]

SCUBA Diving

Silcone greases, of formulas qualified for such use, are often used for lubrication in the

regulators, 'O' rings
and couplings.

Some divers may use high PO2 'enriched' gas mixes containing more than the usual ~21% of Oxygen present in air as one of the ways to reduce the risk of decompression sickness, "the bends", on certain types of dive. Also, oxygen equipment between 60% and 100% is used to 'accelerate' decompression obligations. Silicone grease is used due to the risk that some non-silicone greases can spontaneously combust in the presence of high concentrations of oxygen.[citation needed]

References

  1. doi:10.1002/14356007.a15_423
    .
  2. ^ "Solubility of silicone fluids" (PDF). Retrieved March 6, 2019.
  3. ^ "8462 - Silicone Grease". Retrieved 2022-09-08.
  4. doi:10.1021/om034176w
    .
  5. doi:10.1016/j.ccr.2015.07.005
    .
  6. PMID 17546579
    .
  7. doi:10.1139/cjc-2013-0496
    .
  8. doi:10.1021/om100106e
    .
  9. ^ Nishimura, David. "Pen Repair Don'ts". Vintage Pens. Archived from the original on 16 August 2021. Retrieved 25 April 2022.
  10. ^ MotorBoating. February 2010. pp. 76–.
  11. ^ EEE. Mactier Publishing Corporation. 1965.
  12. ISBN 978-1-305-44593-2
    .
  13. S2CID 37220953
    .
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