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A rubber band is a single molecule, as is a latex glove. The sections of polyisoprene between two adjacent cross-links are called network chains and can contain up to several hundred isoprene units. In natural rubber, each cross-link produces a network node with four chains emanating from it.
The T-V diagram of the rubber band experiment. The decrease in the temperature of the rubber band in a spontaneous process at ambient temperature can be explained using the Helmholtz free energy = where dF is the change in free energy, dL is the change in length, τ is the tension, dT is the change in temperature and S is the entropy.
Rubber was commonly used to make rubber bands and pencil erasers. Rubber produced as a fiber, sometimes called 'elastic', had significant value to the textile industry because of its excellent elongation and recovery properties.
A rubber band ball is a sphere of rubber bands made by using a knotted single band as a starting point and then wrapping rubber bands around the center until the desired size is achieved. The ball is usually made from 100% rubber bands, but some instructions call for using a marble , [ 16 ] a crumpled piece of paper , or a ping-pong ball [ 17 ...
In simple contexts, a single number may suffice to describe the strain, and therefore the strain rate. For example, when a long and uniform rubber band is gradually stretched by pulling at the ends, the strain can be defined as the ratio between the amount of stretching and the original length of the band:
For small values of these changes, ν is the amount of transversal elongation divided by the amount of axial compression. Most materials have Poisson's ratio values ranging between 0.0 and 0.5. For soft materials, [1] such as rubber, where the bulk modulus is much higher than the shear modulus, Poisson's ratio is near 0.5. For open-cell polymer ...
For instance, a rubber band is disordered in the initial state of this region. When stretching the rubber band, you also align the structure to be more ordered. Therefore, when releasing the rubber band, it will spontaneously seek higher entropy state hence goes back to its initial state.
Styrene-butadiene or styrene-butadiene rubber ... Elongation at tear (%) 565 635 Mooney viscosity, 100 °C 48.0 51.6 Glass transition temperature (°C) −65