Polyethylene deformation

Hughes DJ, Mahendrasingam A, Oatway WB, Heeley EL, Martin C, Fuller W (1997) A simultaneous SAXS/WAXS and stress-strain study of polyethylene deformation at high strain rates. Polymer 38 6427... 

Fig. 14.16. Fibrillar deformation zone at a crack tip in a bulk specimen of semicrystalline high-density polyethylene deformed at room temperature (thin section stained with RUO4).

Butler M F, Donald A M and Ryan A J (1998) Time resolved simultaneous small-and wide-angle X-ray scattering during polyethylene deformation. II. Cold drawing of linear polyethylene. Polymer 39 39-52. 

Butler M F and Donald A M (1998) A real-time simultaneous small- and wide-angle X-ray scattering study of in situ polyethylene deformation at elevated temperatures Macromolecules, 31 6234-6249. 

Mourad A-HI, et al. Ultra high molecular weight polyethylene deformation and fracture behaviour as a function of high strain rate and triaxial state of stress. Int J Fract 2003 120(3) 501-15. 

The precise mechanisms by which polyethylene deforms in the solid state are not rigorously understood. Various schemes have been proposed to explain the... 

In this seetion emphasis is placed on the morphological response of polyethylene to tensile deformation, as this is the principal mode by which polyethylene produets deform in nse. Peterlin s model of polyethylene deformation, whieh has been highly inflnential, is discussed first. Subsequently, current views of the yield proeess are outlined, followed by a general discussion of various aspects of deformation. The macroscopic aspects of polyethylene deformation are dealt with in Chapter 5 in the section discussing mechanical properties. 

Fig. 14. Shear viscosity, Tj, and extensional viscosity, Tj as a function of deformation rate of a low density polyethylene (LDPE) at 150°C (111). To convert...

The plastic deformation of such polymers is a major research area and has a triennial series of conferences entirely devoted to it. The process seems to be drastically different from that familiar from metals. A review some years ago (Young 1988) surveyed the available information about polyethylene the yield stress is linearly related to the fraction of crystallinity, and it increases sharply as the thickness... 

In 1955 it was discovered that mixtures of ammonium nitrate and fine coal dust have satisfactory blasting capabilities in large (9 inch) holes used in open-pit coal mines to remove the rock and soil covering the coal. Polyethylene bags containing this material deform to fit the hole and provide moderate water resistance. ANFO is used in open-pit iron and copper mines and for construction such as road building. The mixture is air blown into 2-inch holes or less m maiiv underground mines. 

Other polyolefins A variety of other crystalline polyolefins are available such as polybutene-1 (improved creep resistance over polyethylene), poly-4-methyl pentene-1 (excellent temperature deformation resistance) and ethylene-vinyl acetate (greater flexibility). 

In this review recent theoretical developments which enable quantitative measures of molecular orientation in polymers to be obtained from infra-red and Raman spectroscopy and nuclear magnetic resonance have been discussed in some detail. Although this is clearly a subject of some complexity, it has been possible to show that the systematic application of these techniques to polyethylene terephthalate and polytetramethylene terephthalate can provide unique information of considerable value. This information can be used on the one hand to gain an understanding of the mechanisms of deformation, and on the other to provide a structural understanding of physical properties, especially mechanical properties. 

Couman W.J., Heikens D., and Sjoerdsma S.D., Dilatometric investigation of deformation mechanism in polystyrene-polyethylene block copolymer blend Correlation between Poisson ratio and adhesion. 

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