Wednesday, January 28, 2009

Plastic Flow

The ability for plastic to change shape and absorb impact without shattering is described as plastic flow. Plastics absorb energy instead of shattering. Plastics therefore are used instead of glass to make bulletproof “glass,” windshields, and eyeglass lenses. This property, although very useful, is also not well understood, or, at least, the characteristics of plastics which make this possible are not well understood. Currently research is being conducted to explore this property of plastics at the University of Wisconsin, Madison by chemistry professor Mark Ediger.

Professor Ediger is using nanotechnologies to examine the processes that plastics undergo at high impacts. Nanotechnology has made it possible to understand so much more about the world around us. Nanotechnology has provided new ways of understanding why computer technology works, new ways of visualizing bacteria, and new ways of creating models of behavior. At the nano-level behavior is less easily understood than at a macro level. At the high levels of impact, Ediger has reported that the movement plastics’ constituent molecules “increases dramatically…with molecular rearrangements occurring up to 1,000 times faster than without the stress.” Only recently, have scientists been able to examine molecular behavior on a grand scale and the rearrangements can actually be observed.

It is important to be able to observe the behavior in order to understand the behavior. And it is important to understand the behavior in order to know how the material will react under certain circumstances so that it can be used appropriately. More observation also can lead scientists to understand how a material will react later in its life after undergoing stresses. Ediger hopes to create models of stress on plastics, so that plastics can be better used in the future and so that the life of plastic parts can be extended.


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