Ultra-high molecular weight viscosity

Wagner H.L., and J.G. Dillon. 1988. Viscosity and molecular weight distribution of ultra-high molecular weight polyethylene. / Aypl Poly Sci 36 567-582. 

Figure 8. Comparison of the molecular weights achieved with the different processes. (D.) Disk grade (L.) Low viscosity grade (M.) Medium viscosity grade (H.) High viscosity grade (U.H.) Ultra high molecular weight grade.

Ultra high-molecular weight n. Capillary viscometer for measurement of viscosity molecular weight of polymers in solution advantage over Ostwald-Eenske and Cannon-Fenske is that the measurement is independent of the amount of solution in the viscometer and measurement at a series of concentrations can easily be made by successive dilution also used for measuring intrinsic viscosity. 

The continuous extrusion of the solution of ultra high molecular weight polyethylene (UHMWPE) with a huge jump in viscosity when the solution is formed. 

Table 5.8 lists propylene polymerization data for some of the complexes shown in Figure 5.12. Varieties of other polymer products have been prepared using the D/A-bridged complexes. For example the (Flu)(Cp)ZrCl2 complexes (22a-b) produce ultra-high molecular weight (UHMW) polyethylene with intrinsic viscosities as high as 13.5 d/g. The D/A metallocenes are also effective catalysts for the copolymerization of a-olefins with ethylene to produce medium to ultta-low density polyethylene products. ... 

Lukhovitskii and Karpo [191] established that, in the concentration range accessible for viscometry, the efflux time of a polymer solution is a linear function of the polymer concentration. This is consistent with the Einstein-Simha equation. In the general case, the efflux time of a solution with a polymer concentration tending to zero, T, does not coincide with the efflux time of the pure solvent, T, When the efflux time of a polymer solution is reduced by rather than by (as is done in the standard method), the reduced viscosity becomes independent of the polymer concentration and equal to the intrinsic viscosity. The advantages of the proposed method are especially important for the determination of the intrinsic viscosity (M ) of ultra-high molecular weight polymers. 

Micro-diffraction techniques have been developed mainly at the ID 13 beamline of the European Synchrotron Radiation Facility (ERSF) with a beam size of 3-10 pm for viscose rayon fibers, spider silk, spherulites of P(3HB), and a poly(lactic acid)/(atactic-P(3HB)) blend. Recently, we developed the micro-diffraction techniques with 0.5 pm beam size for analysis ultra-high-molecular-weight-P(3HB) mono-filament ° and P(3HB) copolymer spherulites. To reveal the detail fiber structure and the distribution of two types of molecular conformations in drawn P(3HB-co-8%-3HV) mono-filament, a micro-beam X-ray diffraction experiment was performed with synchrotron radiation at SPring-8, Japan. The beam size was focused to 0.5 pm with the Fresnel Zone Plate technique and the P(3HB-co-8%-3HV) mono-filament was scanned linearly perpendicular to the fiber axis with a step of 4 pm. 

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