Ultra-high-molecular-weight polyethylene: Difference between revisions

UHMWPE is odorless, tasteless, and nontoxic.<ref>Wong, D. W. S.; Camirand, W. M.; Pavlath, A. E.; Krochta, J. M.; Baldwin, E. A. and Nisperos-Carriedo, M. O. (eds.) (1994) "Development of edible coatings for minimally processed fruits and vegetables" pp. 65–88 in ''Edible coatings and films to improve food quality'', Technomic Publishing Company, Lancaster, PA. {{ISBN|1566761131}}.</ref> It embodies all the characteristics of [[high-density polyethylene]] (HDPE) with the added traits of being resistant to concentrated [[acid]]s and [[alkali]]s, as well as numerous organic solvents.<ref>{{cite web |title=PE Material: Porex Porous Polyethylene for Plastic Filter Media |website=porex.com |url=http://www.porex.com/technologies/materials/porous-plastics/pe/ |access-date=2017-02-14}}</ref> It is highly resistant to corrosive chemicals except [[oxidizing acid]]s; has extremely low moisture absorption and a very low [[coefficient of friction]]; is self-lubricating (see [[boundary lubrication]]); and is highly resistant to [[wear#Abrasive wear|abrasion]], in some forms being 15 times more resistant to abrasion than [[carbon steel]]. Its coefficient of friction is significantly lower than that of [[nylon]] and [[polyoxymethylene|acetal]] and is comparable to that of [[polytetrafluoroethylene]] (PTFE, Teflon), but UHMWPE has better abrasion resistance than PTFE.<ref>{{cite journal |title=Free abrasive wear behaviour of UHMWPE composites filled with wollastonite fibres |year=2006 |last1=Tong |first1=Jin |last2=Ma |first2=Yunhai |last3=Arnell |first3=R. D. |last4=Ren |first4=Luquan |journal=Composites Part A: Applied Science and Manufacturing |volume=37 |issue=1 |pages=38–45 |doi=10.1016/j.compositesa.2005.05.023}}</ref><ref>{{cite journal |title=Resistance to particle abrasion of selected plastics |year=1997 |last1=Budinski |first1=Kenneth G. |journal=Wear |volume=203–204 |pages=302–309 |doi=10.1016/S0043-1648(96)07346-2}}</ref>

Polymerization of UHMWPE was commercialized in the 1950s by [[Ruhrchemie]] AG,<ref name="Handbook">{{cite book |author=Kurtz, Steven M. |title=The UHMWPE handbook: ultra-high molecular weight polyethylene in total joint replacement |year=2004 |publisher=Academic Press |isbn=978-0-12-429851-4 |url=https://books.google.com/books?id=bkuFjppEdMcC}}</ref><ref>''Die Aktivitäten der Ruhrchemie AG auf dem Gebiet der Kohlevergasung''. In: ''Glückauf-Forschungshefte'', Jg. 44 (1983), pp. 140–145.</ref> which has changed names over the years. Today UHMWPE powder materials, which may be directly molded into a product's final shape, are produced by, [[Ticona]], [[Braskem]], [[Teijin]] (Endumax), [[Celanese]], and [[Mitsui Chemicals|Mitsui]]. Processed UHMWPE is available commercially either as fibers or in consolidated form, such as sheets or rods. Because of its resistance to wear and impact, UHMWPE continues to find increasing industrial applications, including the automotive and bottling sectors. Since the 1960s, UHMWPE has also been the material of choice for total joint [[arthroplasty]] in [[orthopedic]] and [[vertebral column|spine]] implants.<ref name="Handbook"/>

For personal armor, the fibers are, in general, aligned and bonded into sheets, which are then layered at various angles to give the resulting [[composite material]] strength in all directions.<ref>{{cite web |publisher=Tote Systems Australia |title=Dyneema |url=http://www.tote.com.au/dyneema.htm}}</ref><ref>Bhatnagar, A. (ed.) (2006) ''Lightweight Ballistic Composites: Military and Law-Enforcement Applications''. Honeywell International. {{ISBN|1855739410}}</ref> Recently developed additions to the US Military's [[Interceptor Multi-Threat Body Armor System|Interceptor body armor]], designed to offer arm and leg protection, are said to utilize a form of UHMWPE fabric.<ref>

The use of UHMWPE rope for automotive winching offers several advantages over the more common steel [[wire rope]]. The key reason for changing to UHMWPE rope is improved safety. The lower mass of UHMWPE rope, coupled with significantly lower elongation at breaking, carries far less energy than steel or nylon, which leads to almost no [[snap-back]]. UHMWPE rope does not develop kinks that can cause weak spots, and any frayed areas that may develop along the surface of the rope cannot pierce the skin like broken steel wire strands can. UHMWPE rope is less dense than water, making water recoveries easier as the recovery cable is easier to locate than wire rope. The bright colours available also aid with visibility should the rope become submerged or dirty. Another advantage in automotive applications is the reduced weight of UHMWPE rope over steel cables. A typical {{convert|11|mm|abbr=on}} UHMWPE rope of {{convert|30|m|abbr=on}} can weigh around {{convert|2|kg|abbr=on}}, the equivalent steel wire rope would weigh around {{convert|13|kg|abbr=on}}. One notable drawback of UHMWPE rope is its susceptibility to UV damage, so many users will fit winch covers in order to protect the cable when not in use. It is also vulnerable to heat damage from contact with hot components.