Poly ultrahigh molecular weight

Specialty polymers achieve very high performance and find limited but critical use in aerospace composites, in electronic industries, as membranes for gas and liquid separations, as fire-retardant textile fabrics for firefighters and race-car drivers, and for biomedical applications (as sutures and surgical implants). The most important class of specialty plastics is polyimides. Other specialty polymers include polyetherimide, poly(amide-imide), polybismaleimides, ionic polymers, polyphosphazenes, poly(aryl ether ketones), polyarylates and related aromatic polyesters, and ultrahigh-molecular-weight polyethylene (Fig. 14.9). 

Hsu, L., Syntliesis of ultrahigh molecular weight poly(ethylene terephthalate), J. Macromol. Sci., Phys., B14, 801-813 (1967). 

QIU Qiu, G.-M., Zhu, B.-K., Xu, Y.-Y., and Geckeler, K.E., Synthesis of ultrahigh molecular weight poly(styrene-a/t-maleic anhydride) in supercritical carbon dioxide. 

W. S. Lyoo. Synthesis of ultrahigh molecular weight poly(V-vinylcarbaz-ole) with a high yield using low-temperature heterogeneous-solution polymerization. J. Polym. ScL, Part A Polym. Chem., 39(4) 539-545, February 2001. 

Chabba S, Van Es M, Van Kilnen El, Jongedijik Ml, Vanek D, Gijsman P, et al. Accelerated ageing study of ultrahigh molecular weight poly ethylene yam and unidirectional composites for ballistic applications. J Mater Sci 2007 42 2891-3. 

Ikada Y, K. Nakamura, S. Ogata, et al. 1999. Characterization of ultrahigh molecular weight polyethylene irradiated with gamma-rays and electron beams to high doses. / Poly Sci Part A Poly Chem 37 159-168. 

UHMW-PE Ultrahigh molecular weight poly(ethylene) (also UHMPE) (molecular mass over 3.1 x 106 g/mol)... 

Kuznetsov et al. (2001) used composite membranes, coated with poly(2-dimethyl-amino ethyl)methacrylate (PDMA) and ladder polyorganosiloxane (LP) onto micro-porous aromatic PAI support and PAN, as PV membranes for separating mixtures of methanol and MTBE. It was noticed that the PAI and PAN supports of the multilayer m branes have opposite effects on the total selectivity. High membrane permeability of the multilayer membranes was attained by virtue of the thinness of the interlayer or coating diffusion layer of PDMA with ultrahigh molecular weight. 

Sawatari, C., Satoh, S., and Matsuo, M. 1990. Mechanical properties of ultrahigh molecular weight poly-ethylene-polypropylene blend films produced by gelation/crystallization from solution. Polymer 32 1456-1463. 

The dominant effect of the viscosity of the phases on filler dispersion in polymer blends was illustrated by Feng et al. [3G] in blends of PP and ultrahigh molecular weight PE (UHMWPE). It was observed that CB particles were localized on the interface and were unable to penetrate to the UHMWPE phase due to its high viscosity. Eeng et al. [37] further analyzed the effects of viscosity on filler localization by systematically changing the viscosity of the poly(methyl methacrylate) (PMMA)... 

Solvent-Free Chemical Polymerization [Method Gj. Typically this method of polymerization involves mixing the monomer with an excess of oxidant in a mortar and pestle followed by heating it at an elevated temperature. Ultrahigh molecular weight is obtained for poly(dihexyl-ProDOT) which is the highest reported to date for any oxidative polymerization of oxythiophenes. Various oxidants such as ferric chloride, ferric tosylate, and bromine can be used. 

Polymers are widely used as implant materials because they have physical properties that are similar to those of natural tissues. Examples are long-term and shortterm implants such as blood vessels, heart valves, membranes, mesh prostheses, corneas, tracheal prostheses, dental materials, parts of the nose and ear, knee and hip joints, and others. The synthetic polymers used include polyethylene (PE), particularly ultrahigh molecular weight PE (UHMWPE), poly(ethylene terephthal-ate) (PET), poly(tetrafluoroethylene) (PTFE), polyurethane (PU), and poly(methyl methacrylate) (PMMA). The necessary sterilization before implantation can be performed by y-irradiation, heat (steam), or chemical treatment (ethylene oxide), which should not cause any structural degradation of the polymers. Current challenges in research include the development of biomimetic materials that match both the mechanical and biological properties of their natural counterparts. 

Ahn et al. deduced the concentration profile of heat-induced radicals in a poly-imide resin. In vitro degradation of poly(ortho esters) containing 30 mol% lactic acid has been studied by ID and 2D spectral-spatial ESRI, based on pH-sensitive nitroxide spin probes. Efforts to understand the failure of ultrahigh molecular weight polyethyleue (UHMWPE) in orthopedic components has been studied by spectral-spatial ESRI in Y-irradiated UHMWPE. ... 

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