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Electron-beam processing
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<h2 id="crosslinking">Crosslinking</h2> <p>The <a href="/facts/Cross-link/zeQ9hEAA">cross-linking</a> of polymers through electron-beam processing changes a thermoplastic material into a <a href="/facts/Thermoset/EagnsydT">thermoset</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a><a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> 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:<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p> <ul><li>Thermal: resistance to temperature, aging, low-temperature impact, etc.</li> <li>Mechanical: <a href="/facts/Tensile_strength/Cv2jPplR">tensile strength</a>, modulus, abrasion resistance, pressure rating, creep resistance, etc.</li> <li>Chemical: stress crack resistance, etc.</li> <li>Other: <a href="/facts/Heat_shrink/BmE9g0LC">heat shrink</a> memory properties, <a href="/facts/Positive_temperature_coefficient/Ayc1aNdm">positive temperature coefficient</a>, etc.</li></ul> <p>Cross-linking is the interconnection of adjacent long molecules with networks of bonds induced by chemical treatment or electron-beam treatment. Electron-beam processing of thermoplastic material results in an array of enhancements, such as an increase in tensile strength and resistance to abrasions, stress cracking, and solvents. Joint replacements such as knees and hips are being manufactured from cross-linked <a href="/facts/Ultra-high-molecular-weight_polyethylene/VDuc337R">ultra-high-molecular-weight polyethylene</a> because of the excellent wear characteristics due to extensive research.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p><p>Polymers commonly crosslinked using the electron-beam irradiation process include polyvinyl chloride (<a href="/facts/PVC/9VkegJvr">PVC</a>), <a href="/facts/Thermoplastic_polyurethanes/JUBVY5Ct">thermoplastic polyurethanes</a> and elastomers (TPUs), <a href="/facts/Polybutylene_terephthalate/lPmuvI3m">polybutylene terephthalate</a> (PBT), <a href="/facts/Polyamide/8AmQgTFa">polyamides</a> / <a href="/facts/Nylon/hBvG9bCw">nylon</a> (PA66, <a href="/facts/Nylon_6/8Dtq3N7z">PA6</a>, PA11, PA12), <a href="/facts/Polyvinylidene_fluoride/9LXbA0M4">polyvinylidene fluoride</a> (<a href="/facts/PVDF/9LXbA0M4">PVDF</a>), <a href="/facts/Polymethylpentene/AfbzMzJu">polymethylpentene</a> (PMP), <a href="/facts/Polyethylene/LaaAf4cn">polyethylenes</a> (<a href="/facts/LLDPE/0Qzbr2VU">LLDPE</a>, <a href="/facts/LDPE/qK26w1dJ">LDPE</a>, MDPE, HDPE, <a href="/facts/UHMW/VDuc337R">UHMW</a>PE), and ethylene copolymers such as <a href="/facts/Ethylene-vinyl_acetate/kYxe810A">ethylene-vinyl acetate</a> (EVA) and <a href="/facts/Ethylene_tetrafluoroethylene/CpH0K3oo">ethylene tetrafluoroethylene</a> (ETFE). Some of the polymers utilize additives to make the polymer more readily irradiation-crosslinkable.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p><p>An example of an electron-beam crosslinked part is connector made from polyamide, designed to withstand the higher temperatures needed for soldering with the lead-free solder required by the RoHS initiative.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p><p><a href="/facts/Cross-linked_polyethylene/ayxYuITl">Cross-linked polyethylene</a> piping called PEX is commonly used as an alternative to copper piping for water lines in newer home construction. PEX piping outlasts copper and has performance characteristics that are superior to copper in many ways.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p><p>Foam is also produced using electron-beam processing to produce high-quality, fine-celled, aesthetically pleasing product.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a><a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> </p> <h2 id="long-chain-branching">Long-chain branching</h2> <p>The resin pellets used to produce the foam and thermoformed parts can be electron-beam-processed to a lower dose level than when crosslinking and gels occur. These resin pellets, such as polypropylene and polyethylene can be used to create lower-density foams and other parts, as the "melt strength" of the polymer is increased.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> </p> <h2 id="chain-scissioning">Chain scissioning</h2> <p>Chain scissioning or <a href="/facts/Polymer_degradation/AMv6yVkK">polymer degradation</a> can 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 <a href="/facts/Molecular_weight/FWueGMed">molecular weight</a>. The chain scissioning effects observed in <a href="/facts/Polytetrafluoroethylene/jesBNXKq">polytetrafluoroethylene</a> (PTFE) have been used to create fine micropowders from scrap or off-grade materials.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a> </p><p>Chain scission is the breaking apart of molecular chains to produce required molecular sub-units from the chain. Electron-beam processing provides Chain scission without the use of harsh chemicals usually utilized to initiate chain scission. </p><p>An example of this process is the breaking down of cellulose fibers extracted from wood in order to shorten the molecules, thereby producing a raw material that can then be used to produce biodegradable detergents and diet-food substitutes. </p><p>"Teflon" (PTFE) is also electron-beam-processed, allowing it to be ground to a fine powder for use in inks and as coatings for the automotive industry.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> </p> <h2 id="microbiological-sterilization">Microbiological sterilization</h2> <p>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 <a href="/facts/Sterilization_(microbiology)/ajVXFl7a">sterilization</a> of 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.<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p><p>Sterilization with electrons has significant advantages over other methods of sterilization currently in use. The process is quick, reliable, and compatible with most materials, and does not require any quarantine following the processing.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> For some materials and products that are sensitive to oxidative effects, radiation tolerance levels for electron-beam irradiation may be slightly higher than for gamma exposure. This is due to the higher dose rates and shorter exposure times of e-beam irradiation, which have been shown to reduce the degradative effects of oxygen.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> </p> <h2 id="notes">Notes</h2> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Hamm, Robert W.; Hamm, Marianne E. (2012). Industrial Accelerators and Their Applications. World Scientific. ISBN 978-981-4307-04-8. <a href="978-981-4307-04-8" target="_blank">978-981-4307-04-8</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Imam, Muhammad A; JEELANI, SHAIK; RANGARI, VIJAYA K. (Oct 2015). "Electron-Beam Irradiation Effect on Thermal and Mechanical Properties of Nylon-6 Nanocompoiste Fibers Infused with Diamond and Diamond Coated Carbon Nanotubes". International Journal of Nanoscience. 15 (1n02). World Scientific. doi:10.1142/S0219581X15500313. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Cheng, Zhoung-Yang; Bharti, V.; Mai, Tian; Xu, Tian-Bing; Zhang, Q. M.; Ramotowski, T.; Wright, K. A.; Ting, Robert (Nov 2000). "Effect of High Energy Electron Irradiation on the Electromechanical Properties of Poly(vinylidene Fluoride-Trifluoroethylene) 50/50 and 65/35 Copolymers". IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. 47 (6). IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society: 1296–1307. doi:10.1109/58.883518. PMID 18238675. S2CID 22081881. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Bly, J. H.; Electron Beam Processing. Yardley, PA: International Information Associates, 1988. <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Chmielewski, Andrzej G. (2006). "Worldwide developments in the field of radiation processing of materials in the down of 21st century" (PDF). Nukleonika. 51 (Supplement 1). Institute of Nuclear Chemistry and Technology: S3 – S9. <a href="http://www.ichtj.waw.pl/ichtj/nukleon/back/full/vol51_2006/v51s1p003f.pdf" target="_blank">http://www.ichtj.waw.pl/ichtj/nukleon/back/full/vol51_2006/v51s1p003f.pdf</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Imam, Muhammad A; JEELANI, SHAIK; RANGARI, VIJAYA K. (Oct 2015). "Electron-Beam Irradiation Effect on Thermal and Mechanical Properties of Nylon-6 Nanocompoiste Fibers Infused with Diamond and Diamond Coated Carbon Nanotubes". International Journal of Nanoscience. 15 (1n02). World Scientific. doi:10.1142/S0219581X15500313. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Berejka, Anthony J.; Daniel Montoney; Marshall R. Cleland; Loïc Loiseau (2010). "Radiation curing: coatings and composites" (PDF). Nukleonika. 55 (1). Institute of Nuclear Chemistry and Technology: 97–106. <a href="http://www.nukleonika.pl/www/back/full/vol55_2010/v55n1p097f.pdf" target="_blank">http://www.nukleonika.pl/www/back/full/vol55_2010/v55n1p097f.pdf</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Technology". E-BEAM.[better source needed] <a href="http://www.ebeamservices.com/technology.htm" target="_blank">http://www.ebeamservices.com/technology.htm</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>"Harris Orthopaedics Lab (HOL) - Massachusetts General Hospital, Boston, MA". Archived from the original on 2014-08-26. Retrieved 2014-08-21. <a href="https://web.archive.org/web/20140826160900/http://www.massgeneral.org/research/researchlab.aspx?id=1018" target="_blank">https://web.archive.org/web/20140826160900/http://www.massgeneral.org/research/researchlab.aspx?id=1018</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>"Fluorinated Polymers". BGS. <a href="http://www.bgs.eu/fluorierte_kunststoffe.html?&L=1" target="_blank">http://www.bgs.eu/fluorierte_kunststoffe.html?&L=1</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>"Case Study: Injection Molded Polyamide Parts with Higher Heat Resistance" (PDF). Archived from the original (PDF) on 2014-08-26. Retrieved 2014-08-21. <a href="https://web.archive.org/web/20140826114821/http://www.ebeamservices.com/pdf/xl-pa6-study.pdf" target="_blank">https://web.archive.org/web/20140826114821/http://www.ebeamservices.com/pdf/xl-pa6-study.pdf</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>"Cross-Linking". Iotron Industries: Electron Beam Sterilization Processing Services. Archived from the original on 2012-12-25. Retrieved 2013-02-11. <a href="https://web.archive.org/web/20121225011018/http://www.iotron.com/services/cross-linking/" target="_blank">https://web.archive.org/web/20121225011018/http://www.iotron.com/services/cross-linking/</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>"Technology". Toray Plastics (America), Inc. Archived from the original on 2014-08-26. Retrieved 2014-08-21. <a href="https://web.archive.org/web/20140826114759/http://www.toraytpa.com/polyolefin-foams/technology" target="_blank">https://web.archive.org/web/20140826114759/http://www.toraytpa.com/polyolefin-foams/technology</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>"Electron beam processing, e-beam processing, plastics crosslinking, medical device sterilization - E-BEAM News". Archived from the original on 2014-08-26. Retrieved 2014-08-21. <a href="https://web.archive.org/web/20140826120756/http://www.ebeamservices.com/release0407_c.htm" target="_blank">https://web.archive.org/web/20140826120756/http://www.ebeamservices.com/release0407_c.htm</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>"Polymer Modification". E-BEAM Services. <a href="https://ebeamservices.com/polymer-crosslinking/#foam-film" target="_blank">https://ebeamservices.com/polymer-crosslinking/#foam-film</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Bly, J. H.; Electron Beam Processing. Yardley, PA: International Information Associates, 1988. <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>"Chain Scission". Iotron Industries: Electron Beam Sterilization Processing Services. Archived from the original on 2012-12-25. Retrieved 2013-02-11. <a href="https://web.archive.org/web/20121225005406/http://www.iotron.com/services/chain-scission/" target="_blank">https://web.archive.org/web/20121225005406/http://www.iotron.com/services/chain-scission/</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Singh, A., Silverman, J., eds. Radiation Processing of Polymers. New York, NY: Oxford University Press, 1992. <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>"Electron Beam (E-Beam) Sterilization". Sterigenics.[better source needed] <a href="https://sterigenics.com/technologies/electron-beam/" target="_blank">https://sterigenics.com/technologies/electron-beam/</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>"Material Consideration: Radiation Processing" (PDF). Sterigenics. Retrieved 2025-03-11. <a href="https://sterigenics.com/wp-content/uploads/2018/09/Material-Considerations-Irradiation-Processing_WEB-v3.pdf" target="_blank">https://sterigenics.com/wp-content/uploads/2018/09/Material-Considerations-Irradiation-Processing_WEB-v3.pdf</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> </ol>