Polyethylene fracture

Comparison of the fracture surface of the opaque polyethylene layer between the "good" sample (Figures 65(a) and 65(b)) and the "bad" sample (Figures 65(c) and 65(d)) showed a definite difference in appearance. The "good" sample fracture surface showed evidence of ductility in the polyethylene layer. The polyethylene fracture surface of the "bad" sample showed less elongation and had a cleaner appearance that is characteristic of brittle failure. 

Fig. 10.2. ESR spectra of high density polyethylene fractured in the presence of nitrosobenzene. Observation temperatures are shown on respective spectra. W is extrema separation (outermost separation width) (Ref. )...

Fig. 10.3. X-ray diffraction patterns of high density polyethylene fractured for various time periods shown on respective patterns (Ref.

Fig. 10.6. Variation of extrema separation with temperature of observation for high density polyethylene fractured for I h (A), 4 h (A), 10 h ( ), and 25 h (O) (Ref. )...

Kozlov, G. V, Beloshenko, V. A., Gazaev, M. A. (1996). The Fractal Treament of Polyethylene Fracture at Impact Loading Problemy Prochnosti, 5, 109-113. 

Lustiger A, Markham RL. Importance of tie molecules in preventing polyethylene fracture under long-term loading conditions. Polymer 1983 24(12) 1647-1654. 

Injection moulding and extrusion may be carried out at temperatures in the range of 300-380°C. The polymer has a high melt viscosity and melt fracture occurs at a lower shear rate (about 10 s ) than with low-density polyethylene (about 10 s ) or nylon 66 (about 10 s ). Extruders should thus be designed to operate at low shear rates whilst large runners and gates are employed in injection moulds. 

Occupational health advice as part of primary health care nursing The fracture behaviour of polyethylene - A literature review First aid retention of knowledge survey... 

Narrow molecular weight distribution, which is characteristic of metallocene-based polyethylene (Fig. 7), causes processing difficulty in certain applications due to increased melt pressure, reduced melt strength, and melt fracture [14,15]. This problem can be overcome by blending the metallocene polymer with other prod-... 

The mechanisms by which polymers undergo degradation in the human body are not yet completely understood. Examples of breakdown of these materials are illustrated by the embrittlement and excessive wear of polyester sockets exposed to the mechanical, biochemical and thermal stresses of the physiological milieu, as well as by the fatigue fractures, excessive wear and additional cross-linking (embrittlement) that have been observed in polyethylene sockets. 

Dewatering surfactants can be polyoxyethylene, polyoxypropylene, and polyethylene carbonates [1348] or p-tert-amylphenol condensed with formaldehyde, or they can be composed of a copolymer from 80% to 100% alkyl methacrylate monomers and hydrophilic monomers [777]. Such a well treatment fluid may be used in both fracturing and competition operations to enhance and maintain fracture conductivity over an extended period of production. 

Davis, J.A., Jr. and Rhudy, J.S. "Hydraulic Fracturing of Subterranean Reservoirs Using Polyethylene Oxide-Based Fracturing Fluid," US Patent 3,747,681(1973). 

Figure 64 Optical micrograph of the fracture surface of the bad film. (1) Clear outer polyester layer, (2) middle opaque polyethylene layer, and (3) EVA heat seal layer.

The polyethylene layer shows a series of fault lines that run perpendicular to the direction of applied stress. The fracture surface of the polyethylene is sharp and jagged, and shows no signs of elongation or ductility. Beneath the polyethylene layer "2" was a thin layer ("3") that was identified as ethylene/vinyl acetate copolymer (EVA). The EVA layer did show evidence of ductile failure in the SEM images. 

The number of layers and the approximate thickness of each layer were determined from SEM images of freeze-fractured cross-sections of the films (Figure 65). A diagram of the apparent film construction is presented in Figure 66. The composition and thickness of each layer are shown in Table 15. The center opaque polyethylene layer and the EVA heat seal layer could not be differentiated in the SEM images of the freeze-fractured cross-section of the... 

The ATR-FTIR spectrum of the middle opaque polyethylene layer of the "bad" sample is shown in Figure 70. This spectrum was acquired from the fracture surface where the outer polyester film and tie layer delaminated from the polyethylene layer. The highest-scoring library match in Figure 70 indicates that the middle layer is a polyethylene with a low branch content, most likely a HDPE or a LLDPE, although a much more detailed spectral analysis would be required to confirm this. 

Linear combination of atomic orbitals (LCAO) method, 16 736 Linear condensation, in silanol polycondensation, 22 557-558 Linear congruential generator (LCG), 26 1002-1003 Linear copolymers, 7 610t Linear density, 19 742 of fibers, 11 166, 182 Linear dielectrics, 11 91 Linear elastic fracture mechanics (LEFM), 1 509-510 16 184 20 350 Linear ethoxylates, 23 537 Linear ethylene copolymers, 20 179-180 Linear-flow reactor (LFR) polymerization process, 23 394, 395, 396 Linear free energy relationship (LFER) methods, 16 753, 754 Linear higher a-olefins, 20 429 Linear internal olefins (LIOs), 17 724 Linear ion traps, 15 662 Linear kinetics, 9 612 Linear low density polyethylene (LLDPE), 10 596 17 724-725 20 179-211 24 267, 268. See also LLDPE entries a-olefin content in, 20 185-186 analytical and test methods for,... 

Figure 2 A true positive Tc-hydrazino nicotinamide-polyethylene glycol-liposome scintigram (left) and a false-negative In-labeled polyclonal immunoglobulin G scintigram right) of a patient with painful swelling and redness at the level of an old tibial fracture.

Fig. 6.8. Fracture toughness, K, of short glass fiber-thermoplastics injection molded composites as a function of weight fraction of fiber, fVr. (O) and (A) polyethylene terephthalate (PET) matrix ( ) and (A) polycarbonate (PC) matrix. Notches made transverse (O, ) and parallel (A, A) to the mold fill direction,...

Lauke B. and Schultrich B. (1986a). Calculation of fracture work of short glass fiber reinforced polyethylene for static and dynamic loading rates. Composites Sci. Technol. 26, 1-16. 

Figure 13.3.7 shows scanning electron microscopy (SEM) photographs of the surface of the polyethylene particle after the silica particles were peeled off. The specimen was prepared in the following way. After the composite particles were potted in epoxy resin, the dried resin block was cut using a microtome to produce fine sections. The fracture surface appearance of the polyethylene was then observed under a microscope. The mean depth penetration into the surface of the core particles could be measured using the SEM photographs. Silica 0.3 pan in diameter was embedded in the surface of the polyethylene particles at a depth of 0.03 xm. In... 

Fig. 13.3.7 Typical SEM photographs of a bare polyethylene surface and silica arrangements, embedded in epoxy resin after fracture (a and d) detached silica (0.3 p,m) arrangement after fracture (b) silica (0.3 p,m) arrangement before fracture (c) bare polyethylene surface after fracture (10 p,m).

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