Rubber elasticity balloon

Latex products are derived from a liquid that comes from rubber trees (natural rubber). Latex is widely used in today s modern world—elastic bands in clothing and undergarments, latex or rubber gloves, balloons, baby bottle nipples, rubber bands, toys, condoms, bandages and tapes, and disposable diapers and other products. 

The rubber in a blown-up balloon is stretched in a biaxial fashion. Derive the force-strain relationship under the assumption that the rubber follows the Gaussian statistical theory of rubber elasticity. 

As the demand for rubber increased so did the chemical industry s efforts to prepare a synthetic sub stitute One of the first elastomers (a synthetic poly mer that possesses elasticity) to find a commercial niche was neoprene discovered by chemists at Du Pont in 1931 Neoprene is produced by free radical polymerization of 2 chloro 1 3 butadiene and has the greatest variety of applications of any elastomer Some uses include electrical insulation conveyer belts hoses and weather balloons... 

If you blow up a balloon, energy is stored in it. There is the energy of the compressed gas in the balloon, and there is the elastic energy stored in the rubber membrane itself. As you increase the pressure, the total amount of elastic energy in the system increases. 

To make the flaw grow, say by 1 mm, we have to tear the rubber to create 1 mm of new crack surface, and this consumes energy the tear energy of the rubber per unit area X the area of surface torn. If the work done by the gas pressure inside the balloon, plus the release of elastic energy from the membrane itself, is less than this energy the tearing simply cannot take place - it would infringe the laws of thermodynamics. 

SURFACE TENSION. Fluid surfaces exhibit certain features resembhng the properties of a stretched elastic membrane hence the term surface tension. Thus, one may lay a needle or a safety-razor blade upon the surface of water, and it will lie at rest in a shallow depression caused by its weight, much as if it were on a rubber air-cushion. A soap bubble, likewise, tends to contract, and actually creates a pressure inside, somewhat after the manner of a rubber balloon. The analogy is imperfect, however, since the tension in the rubber increases with the radius of the balloon, and the pressure inside, which would otherwise decrease, remains approximately constant while the liquid film tension remains constant and the pressure in the bubble falls off as the bubble is blown. 

The term surface tension is tied to the concept that the surface stays under a tension. In a way, this is similar to a rubber balloon, where also a force is required to increase the surface area of its rubber membrane against a tension. There is, however, a difference while the expansion of a liquid surface is a plastic process the stretching of a rubber membrane is usually elastic. 

The shape of foam films and border profiles in large interval of foam expansion ratio from 10 to 1500 has been experimentally studied in [83], A regular pentagonal dodecahedron made up of transparent organic glass with an elastic rubber balloon inside it which took the shape of a sphere at inflation (Fig. 1.10) was used as a model of foam cell. 

Balloon attachments are easily constructed as outlined in Fig. 9.12. First the balloon (or double balloon) is pushed over a piece of rubber tubing which is about the same diameter as the balloon neck. This is secured in place using a piece of wire, elastic band, or Parafilm. The open end of the tubing can then be attached to a three-way tap, or to a needle-tubing adapter and needle as shown. It is advisable to seal all joints with Parafilm in order to ensure that there are no leaks. 

Rubber bands have elasticity. They will snap back into their original shape if you stretch them and then let go. Other things made out of rubber show this same elastic property. A balloon will return to its original shape if you let the air out of it. 

The rubber in an inflated balloon is stretched biaxially, with initial diameter t/o and initial thickness of its walls to- This incompressible rubber contains u elastic strands per unit volume. 

A specific device is used for performing the test, known as the rubber balloon apparatus. It consists of a volumetric cylinder, one end of which is made of a thin elastic membrane. The volumetric cylinder is filled with a known mass of water before testing. The device is placed over the hole, and with the aid of low air pressure, the water occupies the available space (Figure 1.16). 

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