SILLY PUTTY

'Silly Putty' (originally called 'nutty putty', and also known as ''Potty Putty'') is a silicone plastic, marketed today as a toy for children, but originally created as a fortuitous accident during the course of research into potential rubber substitutes for use by the United States during World War II.

Contents

Description

Origins of Silly Putty

Variations

Other brands

Homemade variety

Removal

See also

External links

Description

Silly putty is an inorganic polymer, noted for its many unusual characteristics: It bounces, but breaks when given a sharp blow. Yet, it can flow like a liquid and will form a puddle given enough time.
Silly Putty is composed of 65% Dimethyl Siloxane (hydroxy-terminated polymers with boric acid), 17% Silica, quartz crystalline, 9% Thixotrol ST, 4% Polydimethylsiloxane, 1% Decamethyl cyclopentasiloxane, 1% Glycerine, and 1% Titanium Dioxide.
Silly Putty's unusual flow characteristics are due to the ingredient polydimethylsiloxane (PDMS), a viscoelastic liquid. Viscoelasticity is a type of non-Newtonian flow, characterizing material that acts as a viscous liquid over a long time period but as an elastic solid over a short time period. Silly Putty has sometimes been characterized as a dilatant fluid. However, according to the science of rheology, this is not strictly correct and it is more accurate to characterize it as a viscoelastic or thixotropic liquid.
Some time ago, when Silly Putty was applied to newspapers, the loose ink transferred to the Silly Putty, which could then be stretched out. Modern printing processes render this time-honored activity problematic.
Silly Putty is sold as a 0.47 oz (13 g) piece of plastic clay inside an egg-shaped plastic container. It is available in various colors, including glow-in-the-dark and metallic. The brand is owned by the Binney & Smith company, which also owns Crayola crayons. Today, twenty thousand eggs of Silly Putty are produced daily. Since 1950, more than 300 million eggs of Silly Putty have been sold, or approximately 4500 tons.

Origins of Silly Putty

Silly Putty was invented by James Wright of General Electric when he dropped boric acid into silicone oil. He was looking for a substitute for rubber. GE supplied the newly discovered dilatant compound to researchers around the world. None found a use for it, but they all loved playing with it.[1]
In 1943, Dr. Earl Warrick left the Mellon Institute of Industrial Research to join the newly formed Dow Corning Corporation. His research was refocused: help the war effort by developing a synthetic rubber substitute. Although he failed to produce a suitable rubber before the end of the war, one result of his experiments was a silicone bouncing putty. (“Forty Years of Firsts: The Recollections of a Dow Corning Pioneer," by Dr. Earl L. Warrick,
McGraw-Hill Publishing Company, New York, 1990, pp. 27-28.)
The product was then commercialized by Peter Hodgson in 1949 after the marketing expert attended an informal "nutty putty" party where chemists were playing with the substance after hours. Renamed "Silly Putty" because of its main ingredient, silicone, the product was a smash hit.[2]
Raw Silly Putty polymer is available as ''Dow Corning 3179 Dilatant Compound''. There are recipes for homemade silly putty using Elmer's Glue and boric acid. These produce a compound which is similar in chemical structure but is different in the elements which form that structure.
According to an MIT webpage on inventions:
:Ironically, it was only after its success as a toy that practical uses were found for Silly Putty. It picks up dirt, lint and pet hair, and can stabilize wobbly furniture; but it has also been used in stress-reduction and physical therapy, and in medical and scientific simulations. The crew of Apollo 8 even used it to secure tools in zero-gravity.[3]
Although Silly Putty is fundamentally the product of combining boric acid and silicone oil, one of the main ingredients in name-brand Silly Putty is elemental silicon (silicon binds to the silicone and allows the material to bounce 20% higher).

Variations

Other brands

'Thinking Putty', is marketed as an exercise and stress-relief 'toy' for adults, by Crazy Aaron's Puttyworld. Thinking Putty is essentially the same product as Silly Putty, both products using the same base substance, Dow Corning's 3179 Dilatant Compound. Crazy Aaron adds additional colorizing ingredients to this base substance to create the final product. These coloring agents can sometimes give the putty a slightly different texture than the traditional coral-colored Silly Putty, which tends to be a bit stiffer.
Crazy Aaron sells heat sensitive color changing putty, glow-in-the-dark putty, black magnetic putty, and regular colored putty in many hues. It is sold in 1/5 pound metal tins and 1 pound plastic bags. ThinkGeek sells a rebranded version, called 'Smart Mass Thinking Putty' in 1/5 pound tins.

Homemade variety

An undergraduate chemistry experiment is the production of silly putty; this is done by treating a solution of dimethyldichlorosilane in diethyl ether with water (Warning: the reaction of dimethyldichlorosilane with water is violent and generates hydrogen chloride). After washing the ether solution of the silicone oil with aqueous sodium sulfate, the solution is dried before the ether is evaporated off. Powdered boric oxide is added to the oil and then heated to form the Silly Putty. The Silly Putty has boron based crosslinks between the polymer chains. These boron crosslinks can break and form only slowly, hence when the silly putty is hit with a hammer or thrown at the floor it shatters or bounces but when the solid is left for a time in a tray it slowly flows.
A simple school recipe for silly putty requires only plain white liquid glue and liquid starch. You slowly add the liquid starch to the glue, while kneading it together, until the desired consistency is obtained.
Other homemade variants exist, branded under various trademarks and sold via the Internet.

Removal

Silly Putty will stick to soft plastics, rugs, and clothing, but can be removed using rubbing alcohol, codliver oil, or WD-40.

See also

★ Dilatant

★ Non-Newtonian fluid

External links

★ - ''Treating dimethyl silicon polymer with boric acid''

★ - ''Process for making puttylike elastic plastic, siloxane derivative composition containing zinc hydroxide''

★ Official Website of Silly Putty

★ Full story at MIT's Invention Dimension: Silly Putty page

★ Various scientific experiments done with Silicone Putty

★ American Chemical Society "What's that stuff?" page about Silly Putty

★ Dropping a 50lb beach ball-sized sphere of Silly Putty off a parking garage (pics and video)

★ Crazy Aaron's Puttyworld: Thinking Putty

★ Cambridge Polymer Group's rheological experiments on Silly Putty