Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 1028 for “"polyethylene"”.
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Polyethylene-montmorillonite nanocomposites
… to disperse montmorillonite clay (MMT) into polyethylene(PE), the clay sheets need to be rendered organophilic. Masterbatches with a high level (~40 %wt) of organomodified clay can then be dispersed into a host by a simple mechanical process. Two chemically different masterbatches …
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Study of Polyethylene Crystallization
Dans l'industrie, les produits finis en plastique sont fabriqués par diverses techniques de traitement telles que le moulage par compression, le moulage par injection, le moulage par soufflage, l'extrusion, etc. Ces opérations impliquent l'exposition de résines polymères à de nombreux conditions …
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Polyethylene fiber drawing optimization
… future to obtain thermal conductivity values for polyethylene fibers and notice the effect of aligning the molecular chains.
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Molecular deformation mechanisms in polyethylene.
… differences between linear and branched polyethylene before, during and after deformation. Four blends of isotopically labelled polymers of different types, rapidly quenched from the melt, have been studied by Mixed Crystal Infra-red Spectroscopy and Small Angle Neutron Scattering (SANS), …
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Characterization and optimization of polyethylene blends
Several series of polyethylene (PE) blends were prepared where one component is a conventional PE and the second is a conventional linear low-density polyethylene (LLDPE) or a metallocene-catalyzed LLDPE. A two-step isothermal annealing (TSIA) procedure is developed enabling the satisfactorily …
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Degradation studies on recycled Polyethylene terephthalate
This project aims to investigate the influence of UV on the properties under natural and artificial weathering. The real-time outdoor weathering exposures provide the most accurate results but, they are very slow and manufacturers cannot afford to wait in order to see if a new or improved product …
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Condition assessment of polyethylene pipeline systems
… the state of in-service naturally aged polyethylene (PE) buried pipes and to define procedures or techniques available to facilitate the condition assessment programme of PE pipelines systems. The primary goal of this study was to establish a better understanding of the ageing process in …
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Butt fusion welding of polyethylene pipes
… process is extensively used in the joining of polyethylene (PE) pipes by the water and gas industries. This welding process although deceptively simple, is rather poorly understood, with much of the initial developments being of a rather empirical nature. The Water Research centre (WRc) have …
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Environmental degradation of polyethylene-based plastics
The criteria involved in the degradation of polyethylene-based degradable polymer samples have been investigated, with a view to obtaining a clearer mechanism of photo-biodegradation. The compatibility of degradable polymer samples during materials recycling was also studied. Commercial and …
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Strain-induced crystallization of crosslinked polyethylene
… crystallization of ultra high molecular weight polyethylene (UHMWPE) in both the dry and swollen states have been studied using a digital imaging technique coupled with dynamometry. Polymer fibers obtained by spinning a gel of polyethylene in paraffin oil were lightly crosslinked with dicumyl …
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On the Melting and Crystallization of Linear Polyethylene, Poly(ethylene oxide) and Metallocene Linear Low-Density Polyethylene
… and series of narrow molecular weight linear polyethylene and poly(ethylene oxide) fractions were studied using a combination of ultra-fast and conventional differential scanning calorimetry, optical microscopy, small angle X-ray scattering, and wide angle X-ray diffraction. In the case of …
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Puncture Reversal of Polyethylene Ionomers - Mechanistic Studies
… aging time and temperature, changes in the polyethylene matrix lead to complexities in morphology resulting in changes in the magnitude and shape of the creep curves. As a result of the thermodynamic, viscoelastic, and high-speed impact experiments it has been theorized that self-healing can …
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A reactive melt modification of polyethylene terephthalate
… structural and chemorheological modification of polyethylene terephthalate in the melt phase with low molecular weight multifunctional glycidyl compounds as reactive additives. Polyethylene terephthalate undergoes chain extension and/or branching reactions with the additives that result in …
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The mechanical behaviour of polyethylene pipe systems
The design of polyethylene (PE) pipelines for applications in the gas, water and chemical process industries has been based on data mainly obtained from stress rupture testing pipes only. In practice, installations are composed of both extruded pipe and injection moulded fittings which are joined …
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Blending of polyethylene materials for pipe applications
Melt blending of polyethylene, in particularly HDPE and LLDPE, have been shown to be a major success, especially in the film markets. In this thesis studies are reported on the stress rupture performance of pipes produced from selected polyethylene materials blended to a chosen MDPE pipe grade. The …
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Physical ageing in semi-crystalline polyethylene terephthalate
… has been, as far as research shows, no work on Polyethylene Terephthalate (PET) and the effects ageing can have on this polymer. Two sets of testing were performed, the first on a Thermo-mechanical Analyser (TMA) and the second on a Differential Scanning Calorimeter (DSC). The glasstransition …
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Morphology and Properties of Amorphous Polyethylene Terephthalate
Physical and mechanical properties of amorphous polyethylene terephthalate (PET) have been measured. A uniform morphology was observed when PET thin film (ca. 1000 (ANGSTROM)) was ultraquenched from above its equilibrium melting temperature. Sufficiently rapid quenching rate below T(,g) and heating …
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Multimodal Polyethylene-Graphene Nanocomposite via Melt Extrusion
… graphene-based multimodal-high-density polyethylene (HDPE)polymer nanocomposite using cost-effective techniques was pursued in this study. This study reports on the reinforcement of high molecular weight multimodal-high-density polyethylene HDPE by a microwave-induced plasma graphene, …
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Subambient Passive Cooling Enabled by Polyethylene Aerogels
… longstanding challenges by optimizing and using polyethylene aerogel, a solar reflecting, infrared transparent, and vapor permeable thermal insulator, as a cover for radiative and evaporative coolers. We first present the development, characterization, and optimization of polyethylene aerogels to …
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