Ultra-high-molecular-weight

Low-density Medium-density High-density Ultra high-molecular-weight Glass-fiber- reinforced, high-density Ethylene-vinyl acetate copolymer... 

Low Molecular Weight Flocculants - Contrary to the trend to increase molecular weight, which has resulted in the commercial availability of ultra high molecular weight (HMW) flocculants, there are a number of applications where low molecular weight (LMW) flocculants are gaining considerable credibility. 

Assoc. PE-UHMW ultra-high molecular weight... 

Drag Reducers in Detail Ultra-High Molecular Weight Polyethylene... 

The flow of liquid hydrocarbons can be enhanced by introducing into the stream a nonagglomerating suspension of ultra-high molecular weight polyethylene [490,1647] in water with small amounts of surfactant. The finely divided polyethylene is prepared by polymerization and then cryogrinded below the glass-transition temperature. 

Additive-free film samples of isotactic polypropylene (iPP, 30pm Himont Profax resin) and polyethylenes (LLDPE, 120ym, linear low density DuPont Sclair resin, and UHMW-PE, 120wm, ultra high molecular weight, high density Himont LSR 5641-1B resin) were oxidized by exposure in air to y-radiation (AECL Gamma Cell 220, 1.0... 

Many polymer items are designed specifically to make contact with other materials. Where surface contact is concerned, two key properties are coefficient of friction and abrasion resistance. Polymers used in such applications include ultra high molecular weight polyethylene, polyacctal, fluorinated polymers, and natural and synthetic rubbers. Examples that we routinely come across include furniture upholstery, bushings and gears in office equipment, and bicycle tires. Industrial uses include the outer cover of electrical cables, and pipes that convey abrasive liquids such as slurries and powders. 

Figure 15 X-ray intensity measured as a function of the polar angle y for an undrawn ultra-high molecular weight PE film. Incident beam directed through the thickness of the film (A), and parallel to the plane of the film (B). Reproduced with permission from Lafrance et al. [82]. Reprinted with permission of John Wiley 8t Sons, Inc.

The rate of polymerization may be dramatically accelerated upon addition of a bulky Lewis acid. For example, addition of (184) to a sample of living PMMA generated by irradiation of (181)/MMA causes an increase in polymerization rate by a factor of >45,000.444 The dualcomponent systems (181)/(184), and (181)/(185), have been used to prepare monodisperse, ultra-high-molecular-weight samples of PMMA (Mn > 106, Mw/Mn= 1.2).445... 

Fig. 17 Ultra-high molecular weight non-coherent spherical PE particles formed with 25/MgCl2...

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