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 90 for “"semi-crystalline"”.
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Physical ageing in semi-crystalline polyethylene terephthalate
… created, one sample was completely amorphous (0% crystalline), the other samples were 28% crystalline and 65% crystalline. The results showed that physical ageing can take place in PET. The definitive conclusion is that as the crystallinity increased the amount of ageing decreased. This shows that …
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Multiscale Modeling of the Deformation of Semi-Crystalline Polymers
… number density, percent crystallinity, and crystalline and amorphous orientation distributions. Atomistic models and methods have been developed to investigate these structures, particularly the evolution of entanglements during thermo-mechanical deformations. A new method has been created …
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A model treating tensile deformation of semi-crystalline polymers
Semi-crystalline polymeric solids are usually in a state being built up of crystallites and an amorphous phase. A complex structure changing occurs in the polymer materials during the extension process. Uniaxial stretching of a semi-crystalline polymer sample causes the initial spherulitic …
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Thermoelectric and Charge Transport in Doped Semi-Crystalline Polymers
In recent years, organic semiconductors (OSCs) have generated many research interests from both academia and industry due to the exotic properties and potential applications in flexible displays, light-emitting diodes, solar cells as well as thermoelectrics. Compared with their inorganic …
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3D printing of semi-crystalline high-performance polymers for localized production
L'abstract è presente nell'allegato / the abstract is in the attachment
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Evolution of material properties in patterned semi-crystalline structures enabled by frontal polymerization
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-12-01
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Process/Structure/Property Relationships of Semi-Crystalline Polymers in Material Extrusion Additive Manufacturing
… process/structure/property (P/S/P) relationship. Semi-crystalline polymers, with their crystalline nature, possess unique properties such as enhanced mechanical properties and improved chemical resistance. However, due to the inherent processing challenges in MEX of semi-crystalline polymers, the …
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Synthesis and Characterization of Highly Functional Substituted Stilbene Copolymers and Semi-crystalline Poly(aryl ether sulfone)s
… polysulfone containing 50% BP and 50% DHTP was semi-crystalline. This PAES had a melting temperature (Tm) 320°C in the first heating cycle of a DSC measurement and the presence of crystallites was confirmed by wide angle X-ray diffraction (WAXS).
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Determining the constants for an analyzing the predictive capabilities of a gas sorption model for semi-crystalline polymers
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1992.
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Effect of nano-fibers on the stress-strain behavior of semi-crystalline poly(ethylene terephthalate) at different strain rates
… poly(ethylene terephthalate)- glycol (PETG), semi-crystalline PET, and semicrystalline PET with various amounts of nano-fibers added. The stress-strain behavior for each material at several strain rates is presented. A typical stress-strain curve consists of a relatively steep rise in stress …
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Influence of processing on the structure and properties of semi-crystalline polymer systems : 1) biodegradable starch/poly(ethylene-vinyl alcohol) blends and 2) polyolefinic thermoplastics
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1995.
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In-line process measurements for injection moulding control. In-line rheology and primary injection phase process measurements for injection moulding of semi-crystalline thermoplastics, using instrumented computer monitored injection moulding machines, for potential use in closed loop process control
… on product quality are investigated for semi-crystalline thermoplastic materials. A computer based process and machine parameter monitoring system is utilised to provide accurate and precise process data for analysis
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Understanding of the mechanical response of semicrystalline polymers based on the block-like substructure of crystalline lamellae
… of a range of PE and sPP samples as models of semi-crystalline polymer systems under tensile deformation. Splitting the total tensile deformation into elastic and plastic parts shows four characteristic points (A,B,C and D) from the true stress-true strain curves, where the differential …
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Effect of intermediate solvents on poly(ether ether ketone)
… Methylene chloride swelled both amorphous and semi-crystalline PEEK to high degrees, while tetrahydrofuran and acetone swelled amorphous PEEK only. After desorption, the samples were carefully analyzed to characterize solvent-induced crystallization (SINC), which occurred in amorphous PEEK …
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Supramolecular polymer additives to improve the crystallization behavior and optical properties of polybutylene terephthalate and polyamides
… polymers. The physico chemical properties of semi crystalline polymers depend to a large extend on the crystal structure and spherulite size, which can be controlled by nucleating agents. These additives can increase the crystallization temperature and thus reduce cycle times during melt …
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Crystallization Behavior, Tailored Microstructure, and Structure-Property Relationships of Poly(Ether Ketone Ketone) and Polyolefins
… of equilibrium melting temperature (Tmo) for the semi-crystalline polymer poly(ether ketone ketone) (PEKK), 2) increase understanding of the influence of microstructure (random versus blocky) of functionalized semi-crystalline polymers on physical and chemical properties, and 3) understand the …
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Synthesis and Characterization of Hydrophobic-Hydrophilic Multiblock Copolymers for Proton Exchange Membrane Applications
… PEM, Nafion®, were achieved. Another series of semi-crystalline hydrophobic poly(ether ether ketone)-hydrophilic sulfonated poly(arylene ether sulfone) (PEEK-BPSH100) multiblock copolymers was first synthesized and characterized. However due to their semi-crystalline structure, PEEK blocks are …
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Application of Diagnostic Methods to Assess Ageing Processes in Polymers
… to the understanding and assessment of ageing in semi-crystalline polymers through destructive and non-destructive tests, and to study the feasibility of acoustic means to be utilized for future age-monitoring systems. This called for a thorough evaluation of the governing material properties that …
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