Ultrahigh molecular weight fibers

Ultrahigh molecular weight ultra-oriented fibers have outstanding tensile strength and modulus, which suits them for use in bullet proof vests. 

Gao. S. and Zeng, Y. (1993a). Surface modification of ultrahigh molecular weight polyethylene fibers by plasma treatment. I. Improving surface adhesion. J. Appi. Polym. Sci. 47, 2065-2071. 

Several interesting applications, such as insulated wire and cable,6S-69 UV cross-linking of drawn fibers and tapes from ultrahigh-molecular-weight polyethylene are reported in the literature.70-72 Semi-interpenetrating networks (IPN) from acrylates and polyurethanes are suitable as UV-curable adhesives with high elasticity, good impact resistance and excellent adhesion to a variety of substrates.73-74... 

Polymers of MMA, AAc, and MAA were grafted onto an ultrahigh molecular weight polyethylene (UHMWPE) fiber surface after pretreatment with electron beam irradiation [31]. Sundell et al. [32] pretreated a PE film with electron beams to facilitate the graft polymerization of vinyl benzylchloride onto the substrate. The inner surface of porous PE hollow fiber had also been modified by grafting of glycidyl methacrylate (GMA) polymer after electron beam irradiation [33]. 

Extended-chain polyethylene fiber became available commercially in 1984 when DSM, a Dutch firm in the Netherlands, introduced Dyneema , and Mitsui Petrochemicals in Japan announced Tekmilon . Allied Signal of the United States entered the field in 1985 when it introduced Spectra fibers. These materials are characterized by very high strength and modulus, which are achieved by the use of ultrahigh molecular weight polyethylene spun by the gel spinning method into fibers having extended-chain structures and near perfect orientation. 

Ultrahigh molecular weight polyethylene (UHMW PE) is most commonly used for articulation surfaces in joints. It is also used for prosthesis components in total hip replacement. In the latter application, it may be reinforced with carbon fibers to increase wear properties. 

Dupont. Technical guide - kevlar aramid fiber, available http //www2dupontcom/Kevlar/ en US/assets/downloads/KEVLAR Technical Guidepdf [accessed September 2012]. Stein HL. Ultrahigh molecular weight polyethylenes (UHMWPE). In Dostal C, editor. Engineered materials handbook, vol. 2, Engineering plastics. Ohio ASM International 1998. p. 167-71. 

Kwak, G., Fukao, S., Fujiki, M., Sakaguchi, T., Masuda, T. Nanoporous, honeycomb-structured network fibers spun from semiflexible, ultrahigh molecular weight, disubstituted aromatic polyacetylenes superhierarchical structure and unique optical anisotropy. Chem. Mater. 18, 5537-5542 (2006)... 

Polyethylene can be made into a high-strength, high-modulus fiber (tradenamed Spectra by Allied Signal, Inc.) and then into a fabric. The polyethylene is an ultrahigh-molecular-weight polymer. The density of Spectra is the lowest of all fibers, which makes its use in aerospace laminates especially attractive. However, laminates must not be exposed to temperatures over 250°F. Spectra has very attractive electrical properties with low dielectric constant and loss factor. These properties are useful in radomes. Spectra is also used in ballistic applications like helmets and aircraft panels. 

In gel spinning, a variant of solvent spinning, the polymer is fed as a gel instead of a solution. With gel spinning, very high orientation and strength are possible. The most widely known fiber made by this process is Spectra and Dyneema, both made from ultrahigh molecular weight polyethylene. 

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