page_title: Ultra-high-molecular-weight polyethylene
section_title: Fiber
hierarchical_section_title: Ultra-high-molecular-weight polyethylene / Applications / Fiber
caption_attribution_description: English: LIROS Dyneema SK78 hollowbraid line Deutsch: LIROS Dyneema SK78 Hohlgeflecht
context_page_description: Ultra-high-molecular-weight polyethylene is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene, it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. The longer chain serves to transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made.
  UHMWPE is odorless, tasteless, and nontoxic. It embodies all the characteristics of high-density polyethylene with the added traits of being resistant to concentrated acids and alkalis, as well as numerous organic solvents. It is highly resistant to corrosive chemicals except oxidizing acids; has extremely low moisture absorption and a very low coefficient of friction; is self-lubricating; and is highly resistant to 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 acetal and is comparable to that of polytetrafluoroethylene, but UHMWPE has better abrasion resistance than PTFE.
context_section_description: Dyneema and Spectra are brands of lightweight high-strength oriented-strand gels spun through a spinneret.  They have yield strengths as high as 2.4 GPa (2.4 kN/mm² or 350,000 psi) and density as low as 0.97 g/cm³ (for Dyneema SK75). High-strength steels have comparable yield strengths, and low-carbon steels have yield strengths much lower (around 0.5 GPa). Since steel has a specific gravity of roughly 7.8, these materials have a strength-to-weight ratios eight times that of high-strength steels. Strength-to-weight ratios for Dyneema are about 40% higher than for aramid. Dyneema was invented by Albert Pennings in 1963 but made commercially available by DSM in 1990.
  UHMWPE are used as composite plates in armor, in particular, personal armor and on occasion as vehicle armor. 
  Civil applications containing UHMWPE fibers are cut-resistant gloves, bow strings, climbing equipment, automotive winching, fishing line, spear lines for spearguns, high-performance sails, suspension lines on sport parachutes and paragliders, rigging in yachting, 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. 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 Spectra or Dyneema fabric. Dyneema provides puncture resistance to protective clothing in the sport of fencing.
  The usage of Dyneema/Spectra rope for automotive winching offers numerous advantages over the more common steel wire. The key reason for changing to Dyneema rope is the additional safety offered. The lower mass of Dyneema rope, coupled with significantly lower elongation at breaking, carries far less energy than steel or nylon, which leads to almost no-snap back. Dyneema rope does not create kinks that can cause weak spots and also, by being a rope instead of a cable, any frayed sections that may appear along the length of the rope cannot pierce the skin like traditional wire can.
  Dyneema rope is less dense than water, making water recoveries easier as the recovery cable is easier to locate than traditional wire. The bright colours available also aid with visibility should the rope become submerged or dirty.
  Another advantage to automotive applications is the reduced weight of Dyneema rope over traditional steel cables. A typical 11mm Dyneema rope of 30 metres can weigh around 2kg, the equivalent steel rope would weigh around 13kg.  
  One notable drawback of Dyneema rope is its susceptibility to UV damage, meaning many users will fit winch covers in order to protect the cable. 
  Spun UHMWPE fibers excel as fishing line, as they have less stretch, are more abrasion-resistant, and are thinner than traditional monofilament line.
  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. Also, low elasticity translates to low toughness. The fiber's very high lubricity leads to poor knot-holding ability, and 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.
  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 as a lighter alternative to steel wires.
  It is used in skis and snowboards, often in combination with carbon fiber, reinforcing the fiberglass composite material, adding stiffness and improving its flex characteristics.  The UHMWPE is often used as the base layer, which contacts the snow, and includes abrasives to absorb and retain wax.
  It is also used in lifting applications for manufacturing low weight, and heavy duty lifting slings. Due to it
caption: LIROS Dyneema hollow
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