Silly Putty is a material based on a viscoelastic liquid silicone polymer that exhibits interesting physical properties. Being a type of non-Newtonian fluid it acts as a viscous liquid over a long time period but as an elastic solid over a short time period. The material, which was accidentally invented during World War II by Scottish engineer James Wright, was supposed to become a synthetic substitute for rubber. Institute Materiability. Instructions Manuel Kretzer.
Duration 10 min. Level Easy. Corning Glass Works, who was also developing a substitute for rubber, applied for a patent in and received it in for treating dimethyl silicone polymer with boric oxide.
Wright applied for his patent in In any event, Wright is still officially credited with the invention. By , General Electric GE had shared this discovery with scientists around the world, only to find that none of them, including those at the U. War Production Board, found it more practical than the synthetic rubber already then being produced. Several years later, an unemployed copywriter named Peter Hodgson recognized its marketing potential as a children's toy, after first seeing it advertised at a local toy store as an adult gift.
Hodgson bought the production rights from GE and renamed it Silly Putty, packaging it in plastic eggs because Easter was on the way. However, by Silly Putty was most popular with kids ages six to 12 years old. By the time Hodgson died in , Silly Putty had made him a multi-millionaire. It was only after its success as a toy that practical uses were also found for Silly Putty. It picks up dirt, lint, and pet hair, and can stabilize wobbly furniture.
It has also been used in stress-reduction and physical therapy athletes have used it to strengthen their grip , and in other medical and scientific situations like smoking cessation programs. In , the Apollo 8 astronauts carried Silly Putty into space in a specially designed sterling silver egg to alleviate boredom and help fasten down tools in the weightless environment. The Columbus Zoo in Ohio has even used it to make casts of the hands and feet of gorillas for educational purposes.
The eight million units produced in is four times what was produced in If you pull it quickly, it breaks. It bounces like a rubber ball, but, under very high impact conditions, it shatters. The secret to the behavior of bouncing putty lies in the cross-linking. In the polymer, the boron links polysilicone chains together.
However, this is a dynamic linkage. Thermal motion in the molecule can break the linkage allowing it to slide to a new position along the chain where it re-attaches. A pair of chains can move past each other when the cross-linking bonds are temporarily broken. The putty is able to be stretched when deformation occurs on a time scale that is slower than the cross-link bond break-and-reconnect rate.
If the material is deformed too rapidly, it acts as a rigid stubstance because there is not time for the cross-links to be reconnected after they break. If the deformation is only somewhat faster than the breaking-reconnecting rate, the chains will move some then snap back elastically giving the bouncing behavior.
If the deformation is very rapid, the cross-links break but do not reconnect separating the chains, snapping the sample into pieces. Hitting a sample with a hammer causes it to shatter. Warming a sample of putty causes the disconnection-reconnection rate to increase; freezing the sample, decreases the rate. This part of the procedure must be carried out in the fume hood because the hydrolysis reaction releases toxic hydrogen chloride gas. The dichlorodimethysilane is very sensitive to moisture in the atmosphere so make your transfer quickly.
Add 40 mL of anhydrous diethyl ether and hydrolyze the silane by dropwise addition of 40 mL of water with constant stirring. The water must be added slowly at first, or the exothermic evolution of the HCl gas will be extremely vigorous boiling your ether away. Have an ice water bath available to slow your reaction if the hydrolysis becomes too vigorous. After adding about 10 mL of water, you should be able to increase the rate of addition. When all the water has been added, let the mixture stir for a few minutes and then transfer it to a mL separatory funnel.
Separate the layers discarding the aqueous layer. Wash the ether layer with three mL portions of 1 M sodium carbonate solution to neutralize residual acid remember that neutralization of an acid by carbonate solution evolves carbon dioxide gas! Keep logged in. Cookies deactivated. To use all functions of this page, please activate cookies in your browser.
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