Silicone resin

Clear Museum Gel

Description

A Polymer that contains Silicon, Carbon, and Oxygen. Silicone resins were first discovered by F. Kipping in England in 1904, but were not commercially produced until 1943 by Dow Corning. They were called silicones because their empirical formula (R2SiO) is similar to that for ketones (R2CO) (Lewis, 1993). Silicone resins are made by the room-temperature vulcanization (RTV) of silicone oils. They can cure either with moisture in the air (single-component system) or by the addition of a peroxide catalyst (two-component system). Once cured, silicone resins are chemically inert and can exist as elastomers and resins (both Thermoset and Thermoplastic). They function over a wide temperature range, are water repellent and have very poor adhesion. Silicones are used as sealants, molding compounds, varnishes, enamels, gaskets, implants, and unbreakable windows. The use of silicone resins for preparing molds of museum objects is not recommended as residual curing compounds, release agents, and uncured silicone oils can stain porous materials and corrode metals.

Synonyms and Related Terms

SI; polysiloxane; resina de silicona (Esp.); résine silicone (Fr.); resina siliconica (It.); resina de silicone (Port.); organosiloxane; polymethyl siloxane; polydimethylsiloxane; RTV (room temperature vulcanization)

Examples: Silastic [Dow]; Clear Museum Gel [Ready America]

Other Properties

Properties include chemical inertness, thermal stability, low surface tension, and high compressibility.

Some silicone resins do not burn, others burn slightly with yellow flame and gray smoke.

Water repellent. Most are stable to about 300C.

Density	0.80

Hazards and Safety

May contain Acetone or Methylene chloride as a solvent.

Single component silicone resins release Acetic acid or Methanol during cure.

Additional Information

º J. P.Maish, "Silicone rubber staining of terracotta surfaces", Studies in Conservation 39:250–56, 1994.

Comparisons

General Characteristics of Polymers

Physical Properties for Selected Thermoset Resins

Sources Checked for Data in Record

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 719

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Theodore J. Reinhart, 'Glossary of Terms', Engineered Plastics, ASM International, 1988

• Hoechst Celanese Corporation, Dictionary of Fiber & Textile Technology (older version called Man-made Fiber and Textile Dictionary, 1965), Hoechst Celanese Corporation, Charlotte NC, 1990

• Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979

• Thomas C. Jester (ed.), Twentieth-Century Building Materials, McGraw-Hill Companies, Washington DC, 1995

• Website address 1 Comment: History of Plastics at www.nswpmith.com.au/historyofplastics.html