Ultra-high-molecular-weight polyethylene
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the
UHMWPE is odorless, tasteless, and nontoxic.
Development
Polymerization of UHMWPE was commercialized in the 1950s by
UHMWPE fibers branded as Dyneema, commercialized in the late 1970s by the Dutch chemical company DSM, and as Spectra, commercialized by Honeywell (then AlliedSignal), are widely used in ballistic protection, defense applications, and increasingly in medical devices, sailing, hiking equipment, climbing, and many other industries.
Structure and properties
UHMWPE is a type of
When formed into fibers, the polymer chains can attain a parallel orientation greater than 95% and a level of crystallinity from 39% to 75%. In contrast, Kevlar derives its strength from strong bonding between relatively short molecules.
The weak bonding between olefin molecules allows local thermal excitations to disrupt the crystalline order of a given chain piece-by-piece, giving it much poorer heat resistance than other high-strength fibers. Its
The simple structure of the molecule also gives rise to surface and chemical properties that are rare in high-performance polymers. For example, the
Under tensile load, UHMWPE will deform continually as long as the stress is present—an effect called creep.
When UHMWPE is
Production
Ultra-high-molecular-weight polyethylene (UHMWPE) is
UHMWPE is processed variously by
. Several European companies began compression molding UHMWPE in the early 1960s. Gel-spinning arrived much later and was intended for different applications.In gel spinning a precisely heated gel (of a low concentration of UHMWPE in an oil) is
Applications
Fiber
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Dyneema and Spectra are
Derivatives of UHMWPE yarn are used in composite plates in
, kites, and kite lines for kites sports.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.[14][15] Recently developed additions to the US Military's Interceptor body armor, designed to offer arm and leg protection, are said to utilize a form of UHMWPE fabric.[16] A multitude of UHMWPE woven fabrics are available in the market and are used as shoe liners, pantyhose,[17] fencing clothing, stab-resistant vests, and composite liners for vehicles.[18]
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 11 mm (0.43 in) UHMWPE rope of 30 m (98 ft) can weigh around 2 kg (4.4 lb), the equivalent steel wire rope would weigh around 13 kg (29 lb). 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.
Spun UHMWPE fibers excel as fishing line, as they have less stretch, are more
In climbing, cord and webbing made of combinations of UHMWPE and nylon yarn have gained popularity for their low weight and bulk. They exhibit very low elasticity compared to their nylon counterparts, which translates to low toughness. The fiber's very high lubricity causes poor knot-holding ability, and it is mostly used in pre-sewn 'slings' (loops of webbing)—relying on knots to join sections of UHMWPE is generally not recommended, and if necessary it is recommended to use the triple fisherman's knot rather than the traditional double fisherman's knot.[19][20]
Ships' hawsers and cables made from the fiber (0.97 specific gravity) float on sea water. "Spectra wires" as they are called in the towing boat community are commonly used for face wires [21] as a lighter alternative to steel wires.
It is used in skis and snowboards, often in combination with
It is also used in lifting applications, for manufacturing low weight, and heavy duty lifting slings. Due to its extreme abrasion resistance it is also used as an excellent corner protection for synthetic lifting slings.
High-performance lines (such as backstays) for sailing and parasailing are made of UHMWPE, due to their low stretch, high strength, and low weight.[22] Similarly, UHMWPE is often used for winch-launching gliders from the ground, as, in comparison with steel cable, its superior abrasion resistance results in less wear when running along the ground and into the winch, increasing the time between failures. The lower weight on the mile-long cables used also results in higher winch launches.
UHMWPE was used for the 30 km (19 mi) long, 0.6 mm (0.024 in) thick space tether in the ESA/Russian Young Engineers' Satellite 2 of September, 2007.[23]
Dyneema Composite Fabric (DCF) is a laminated material consisting of a grid of Dyneema threads sandwiched between two thin transparent polyester membranes. This material is very strong for its weight, and was originally developed for use in racing yacht sails under the name 'Cuben Fiber'. More recently it has found new applications, most notably in the manufacture of lightweight and ultralight camping and backpacking equipment such as tents, backpacks, and bear-proof food bags.
In archery, UHMWPE is widely used as a material for bowstrings because of its low creep and stretch compared to, for example,
In
Medical
UHMWPE has a clinical history as a biomaterial for use in hip, knee, and (since the 1980s), for spine implants.[1] An online repository of information and review articles related to medical grade UHMWPE, known as the UHMWPE Lexicon, was started online in 2000.[24]
Joint replacement components have historically been made from "GUR" resins. These powder materials are produced by Ticona, typically converted into semi-forms by companies such as Quadrant and Orthoplastics,[1] and then machined into implant components and sterilized by device manufacturers.[25]
UHMWPE was first used clinically in 1962 by Sir John Charnley and emerged as the dominant bearing material for total hip and knee replacements in the 1970s.[24] Throughout its history, there were unsuccessful attempts to modify UHMWPE to improve its clinical performance until the development of highly cross-linked UHMWPE in the late 1990s.[1]
One unsuccessful attempt to modify UHMWPE was by blending the powder with carbon fibers. This reinforced UHMWPE was released clinically as "Poly Two" by Zimmer in the 1970s.[1] The carbon fibers had poor compatibility with the UHMWPE matrix and its clinical performance was inferior to virgin UHMWPE.[1]
A second attempt to modify UHMWPE was by high-pressure recrystallization. This recrystallized UHMWPE was released clinically as "Hylamer" by DePuy in the late 1980s.[1] When gamma irradiated in air, this material exhibited susceptibility to oxidation, resulting in inferior clinical performance relative to virgin UHMWPE. Today, the poor clinical history of Hylamer is largely attributed to its sterilization method, and there has been a resurgence of interest in studying this material (at least among certain research circles).[24] Hylamer fell out of favor in the United States in the late 1990s with the development of highly cross-linked UHMWPE materials, however negative clinical reports from Europe about Hylamer continue to surface in the literature.
Highly cross-linked UHMWPE materials were clinically introduced in 1998 and have rapidly become the standard of care for
In 2007, manufacturers started incorporating anti-oxidants into UHMWPE for hip and knee arthroplasty bearing surfaces.[1] Vitamin E (a-tocopherol) is the most common anti-oxidant used in radiation-cross-linked UHMWPE for medical applications. The anti-oxidant helps quench free radicals that are introduced during the irradiation process, imparting improved oxidation resistance to the UHMWPE without the need for thermal treatment.[26] Several companies have been selling antioxidant-stabilized joint replacement technologies since 2007, using both synthetic vitamin E as well as hindered phenol-based antioxidants.[27]
Another important medical advancement for UHMWPE in the past decade has been the increase in use of fibers for
Manufacturing
UHMWPE is used in the manufacture of PVC (vinyl) windows and doors, as it can endure the heat required to soften the PVC-based materials and is used as a form/chamber filler for the various PVC shape profiles in order for those materials to be 'bent' or shaped around a template.
UHMWPE is also used in the manufacture of hydraulic seals and bearings. It is best suited for medium mechanical duties in water, oil hydraulics, pneumatics, and unlubricated applications. It has a good abrasion resistance but is better suited to soft mating surfaces.
Wire and cable
Fluoropolymer / HMWPE insulation cathodic protection cable is typically made with dual insulation. It features a primary layer of a fluoropolymer such as ECTFE which is chemically resistant to chlorine, sulfuric acid, and hydrochloric acid. Following the primary layer is an HMWPE insulation layer, which provides pliable strength and allows considerable abuse during installation. The HMWPE jacketing provides mechanical protection as well.[29]
Marine infrastructure
UHMWPE is used in marine structures for the mooring of ships and floating structures in general. The UHMWPE forms the contact surface between the floating structure and the fixed one. Timber was and is used for this application also. UHMWPE is chosen as facing of fender systems for berthing structures because of the following characteristics:[30]
- Wear resistance: best among plastics, better than steel
- Impact resistance: best among plastics, similar to steel
- Low friction (wet and dry conditions): self-lubricating material
See also
- Low-density polyethylene (LDPE)
- Medium-density polyethylene (MDPE)
- Twaron
- IPX Ultra-high-molecular-weight polyethylene
References
- ^ ISBN 978-0-12-429851-4.
- ^ Stein, H. L. (1998). Ultrahigh molecular weight polyethylenes (uhmwpe). Engineered Materials Handbook, 2, 167–171.
- ISBN 1566761131.
- ^ "PE Material: Porex Porous Polyethylene for Plastic Filter Media". porex.com. Retrieved 2017-02-14.
- .
- .
- ^ Die Aktivitäten der Ruhrchemie AG auf dem Gebiet der Kohlevergasung. In: Glückauf-Forschungshefte, Jg. 44 (1983), pp. 140–145.
- ^ ultra high molecular weight polyethylene; UHMWPE. chemyq.com
- ISBN 9780824794705.
- ^ Hoechst: Annealing (Stress Relief) of Hostalen GUR
- S2CID 137384856. Archived from the original(PDF) on 2019-02-17. Retrieved 2019-07-13.
- ^ Crouch, Ian. 2016. The Science of Armour Materials. P229. Woodhead Publishing.
- ^ "The story of Dyneema®". Dyneema® Project.
- ^ "Dyneema". Tote Systems Australia.
- ISBN 1855739410
- ^ Monty Phan; Lou Dolinar (February 27, 2003). "Outfitting the Army of One – Technology has given today's troops better vision, tougher body armour, global tracking systems – and more comfortable underwear" (Nassau and Queens ed.). Newsday. pp. B.06.
- ^ "Sheertex creates world's toughest sheer pantyhose". Knitting Industry. Inside Textiles Ltd. 20 September 2019.
- ^ "UHMWPE Fabrics". Akiro Protech.
- ^ Moyer, Tom; Tusting, Paul & Harmston, Chris (2000). "Comparative Testing of High Strength Cord" (PDF).
- ^ "Cord testing" (PDF). Retrieved May 7, 2020.
- ^ A cable used to secure a barge to a towboat Smith Maritime Ocean Towing & Salvage Services (2024). "Glossary of Terms". Archived from the original on 2019-12-26. Retrieved 2024-04-23.
- ^ "Spectra® and Dyneema® | Bally Ribbon Mills". Bally Ribbon Mills. Retrieved 2016-06-07.
- PMID 17898730.
- ^ a b c d e UHMWPE Lexicon. Uhmwpe.org. Retrieved on 2012-06-30.
- ^ GHR HMW-PE and VHMW-PE. ticona.com
- ^ Wannomae, K. K., Micheli, B. R.; Lozynsky, A. J. and Muratoglu, O. K. (2010) "A new method of stabilising irradiated UHMWPE using Vitamin E and mechanical annealing". 56th Annual Meeting of the Orthopedic Research Society, 2290.
- ^ Spiegelberg, S.H. (2012). "UHMWPE for total joint arthroplasty: Past, present, and future". Bonezone.
- ^ "DSM introduces Dyneema Purity® Black fiber, the first black medical-grade UHMWPE fiber". DSM. 2017.
- ^ "Cathodic Protection" Archived 2021-08-02 at the Wayback Machine. Performance of XLPE cable.
- ^ "UHMWPE for marine structures". Retrieved May 7, 2020.
Further reading
- Southern et al., The Properties of Polyethylene Crystallized Under the Orientation and Pressure Effects of a Pressure Capillary Viscometer, Journal of Applied Polymer Science vol. 14, pp. 2305–2317 (1970).
- Kanamoto, On Ultra-High Tensile by Drawing Single Crystal Mats of High Molecular Weight Polyethylene, Polymer Journal vol. 15, No. 4, pp. 327–329 (1983).
External links
- US Patent 5342567 Process for producing high tenacity and high modulus polyethylene fibers, issued 1994-08-30
- Polymer Gel Spinning Machine Christine A. Odero, MIT, 1994
- Patent application 20070148452 High strength polyethylene fiber, 2007-06-28
- Analytical techniques to characterize radiation effects on UHMWPE Archived 2014-04-24 at the Wayback Machine
- Next generation orthopedic implants using UHMWPE Archived 2014-04-24 at the Wayback Machine
- Highly crosslinked VE-UHMWPE for hip and knee replacements Archived 2014-04-24 at the Wayback Machine
- UHMWPE Characteristics, Processing Methods, Applications Archived 2019-07-05 at the Wayback Machine
- Polyethylene UHMWPE HDPE LDPE LLDPE – What are the differences? Archived 2021-05-15 at the Wayback Machine
- HMPE Fibre – How is it made?