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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 30 for “"liquid crystalline polymers"”.
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Fiber spinning and rheology of liquid-crystalline polymers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1994.
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A Least Squares Closure Approximation for Liquid Crystalline Polymers
… schemes for the Doi-Hess kinetic theory of liquid crystalline polymers is provided. A new closure scheme is devised based on a least squares fit of a linear combination of the Doi, Tsuji-Rey, Hinch-Leal I, and Hinch-Leal II closure schemes. The orientation tensor and rate-of-strain tensor …
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Selection of Thermotropic Liquid Crystalline Polymers for Rotational Molding
Thermotropic liquid crystalline polymers (TLCPs) possess a number of physical and mechanical properties such as: excellent chemical resistance, low permeability, low coefficient of thermal expansion, high tensile strength and modulus, and good impact resistance, which make them desirable for use in …
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Studies on the rheology and morphology of thermotropic liquid crystalline polymers
… that the physical properties of as-processed liquid crystalline polymers are highly dependent on the thermal and deformation histories of the materials experienced. The purpose of this study has been to examine the effect of thermal history on the rheology and morphological texture for several …
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The rheology and structure of thermotropic liquid crystalline polymers in extensional flow
… measured in order to determine the behavior of liquid crystalline polymer systems and to establish whether this behavior is different from that for isotropic flexible-chain polymer melts and isotropic systems of rodlike polymers. In order to accomplish this a rotary clamp extensional rheometer …
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The synthesis, characterization and optical properties of novel diacetylene-containing aromatic liquid crystalline polymers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1993.
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The Effects of Processing Conditions on Thermoplastic Prototypes Reinforced with Thermotropic Liquid Crystalline Polymers
… strands reinforced with continuous thermotropic liquid crystalline polymer (TLCP) fibrils were generated in a novel dual extruder process. Strands were then re-extruded to form short fiber composite monofilaments that were used as feed stock in the FDM 1600 rapid prototyping system. Prototypes …
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A study of processing methods for producing biaxial orientation in thermotropic liquid crystalline polymers
Four methods of biaxial deformation were considered in an attempt to obtain biaxial orientation and properties in two thermotropic copolyesters: hydroxybenzoic acid-co-polyethylene terephthalate (HBA/PET) and hydroxybenzoic acid/2, 6 hydroxynaphthoic acid (HBA/HNA). They consisted of solid phase …
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Processing and properties of composites based on high density polyethylene and thermotropic liquid crystalline polymers
… density polyethylene (HDPE) and thermotropic liquid crystalline polymers (TLCPs). Strands of HDPE reinforced with TLCPs were generated using a novel dual extruder mixing technique. It was shown that the strength and modulus of the strands improved with increased strand drawing. Post-processing …
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Studies of blends containing liquid crystalline polymers with PET and related investigations of hydroquinone/biphenol polysulfone systems
… cast films prepared from blends of thermotropic liquid crystalline copolyesters with polyethylene terephthalate (PET). Data were obtained which showed not only the temperature dependence of the moduli and stress-strain behavior but also the orientation effects that must be prevalent in order to …
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Multiscale simulation of viscoelastic flows : applications to kinetic theory models of polymer melts and liquid crystalline polymers
… to simulate the behavior of polymeric liquids in a fabrication process. These simulation approaches require solution of the coupled set of the equations of change, the governing equations from kinetic theory, and the flux expressions that map molecular configurations to macroscopic …
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Linking the Rheological Behavior to the Processing of Thermotropic Liquid Crystalline Polymers in the Super-cooled State
Thermotropic liquid crystalline polymers (TLCPs) have attracted great interest because of the combination of their promising properties, which includes high stiffness and strength, excellent processability, and outstanding chemical resistance. TLCPs exhibit inherently low viscosity relative to many …
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The development of a dual extrusion blending process and composites based on thermotropic liquid crystalline polymers and polypropylene
… (DEP) which is used to blend thermotropic liquid crystalline polymers (TLCPs) with thermoplastics, determine the mechanism by which TLCP morphology is developed in the DEP and to determine the optimal properties possible in composite materials generated from the blends. The DEP consists of …
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The processing of microcomposites based on polypropylene and two thermotropic liquid crystalline polymers in injection molding, sheet extrusion, and extrusion blow molding
… pregenerated microfibrils of thermotropic liquid crystal polymers (TLCPs), referred to as microcomposites. The processing methods used are injection molding, sheet extrusion, and extrusion blow molding. The TLCPs used are HX6000 and Vectra A950. The microcomposites are produced by drawing …
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Structure, Thermodynamics, Mechanical Properties and Glassy Dynamics in Anisotropic Polymeric Materials
… relaxation regime in deeply supercooled polymer liquids. Alignment and/or deformation modify thermodynamic and structural properties thereby inducing anisotropic segmental dynamics. Either suppression or elevation of ( Tc) is predicted depending on the nature of anisotropy. Results have been …
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Reclamation and Reprocessing of Thermotropic Liquid Crystalline Polymer from Composites of Polypropylene Reinforced with Liquid Crystalline Polymer
… considerable interest in the use of thermotropic liquid crystalline polymers (TLCPs) to reinforce thermoplastic materials. In a novel process developed by Baird and coworkers, wholly thermoplastic composites are produced via a patented, dual extrusion process. This unique process yields a fiber …
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Poly(pyridinium salt)s exhibiting liquid-crystalline and light-emitting properties
… and triflimide counterions that possess both liquid-crystalline properties as well as light emitting properties. Both the solution-state and solid-state emission behavior of these synthesized materials were investigated. They possessed several emission peaks in their spectra ranging from 280 …
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Synthesis and characterization of polyether-ester liquid crystalline polyesters and poly(arylene ether ketone)-lcp segmented copolymers
… were found to be useful for synthesizing LCP copolymers and segmented copolymers. A variety of polyarylates based on 5-tertiary butylisophthalic acid were synthesized via melt acidolysis techniques. The resulting high molecular weight polyarylates were amorphous polymers and the t-butyl groups …
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Fundamental aspects of the tribological behavior of poly(ether-ether-ketone)-based in-situ composites at elevated temperatures
… of engineering thermoplastics and thermotropic liquid crystalline polymers (TLCPs) are recently developed, innovative polymeric materials, which have been reported to exhibit outstanding property profiles. These profiles include superior mechanical properties, excellent thermal and dimensional …
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