- Electron beam processing
Electron beam processing involves irradiation of products using a high-energy
electron beamaccelerator. Electron beam accelerators utilize an on-off technology, with a common design being similar to that of a cathode raytelevision.
Electron beam processing is used in industry primarily for three product modifications:
* crosslinking of polymer-based products to improve mechanical, thermal, chemical and other properties,
* material degradation often used in the recycling of materials, and
* sterilization of medical and pharmaceutical goods. [Bly, J.H.; Electron Beam Processing. Yardley, PA: International Information Associates, 1988.]
cross-linkingof polymers through electron beam processing changes a thermoplastic material into a thermoset. When polymers are crosslinked, the molecular movement is severely impeded, making the polymer stable against heat. This locking together of molecules is the origin of all of the benefits of crosslinking, including the improvement of the following properties:Thermal: resistance to temperature, aging, low temperature impact, etc.Mechanical: tensile strength, modulus, abrasion resistance, pressure rating, creep resistance, etc.Chemical: stress crack resistance, etc.Other: heat shrinkmemory properties, positive temperature coefficient, etc. [ [http://www.ebeamservices.com/default.htm electron beam processing, sterilization, crosslinking, mail sanitation, decontamination, irradiation - ebeam ] ]
Chain scissioning or
polymer degradationcan also be achieved through electron beam processing. The effect of the electron beam can cause the degradation of polymers, breaking chains and therefore reducing the molecular weight. The chain scissioning effects observed in polytetrafluoroethylene (PTFE) have been used to created fine micropowders from scrap or off-grade materials. [Bly, J.H.; Electron Beam Processing. Yardley, PA: International Information Associates, 1988.] Sterilization (microbiology)
Electron beam processing has the ability to break the chains of DNA in living organisms, such as bacteria, resulting in microbial death and rendering the space they inhabit sterile. E-beam processing has been used for the
sterilizationof medical products and aseptic packaging materials for foods as well as disinfestation, the elimination of live insects from grain, tobacco, and other unprocessed bulk crops. [Singh, A., Silverman, J., eds. "Radiation Processing of Polymers". New York, NY: Oxford University Press, 1992.]
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