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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 193 for “"polycarbonate"”.
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Thermal Degradation Studies of Polycarbonate
… The current study focuses on bisphenol A polycarbonate and tracks changes in the properties of this material as a function of the degree of degradation, t. For the purposes of the present research, the environmental effects have been limited to those associated with elevated temperature, …
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Polymer Crystallization: Polycarbonate and Polybutene-1
The crystallization of polycarbonate from the glassy state was examined using thin ($\sim$1000A), solution cast films and thicker (0.16 and 1.5 mm) compression molded films. A detailed study of the crystallization process in the thin films, as observed by transmission electron microscopy, revealed …
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Characterization of Crazing Properties of Polycarbonate
… was to characterize the craze growth behavior of polycarbonate (PC) as a function of stress level, model the residual mechanical properties of PC at various craze levels and strain rates, and determine if the total surface area of crazing is the sole factor in residual properties or if the crazing …
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Deformation and fracture of polycarbonate and rubber-modified polycarbonate under controlled temperature, deformation rate, and notch stress triaxiality
The deformation and fracture of polycarbonate and polycarbonate toughened with methyl-methacrylate shell/polybutadiene core sub-micron particles are investigated. The effects of strain rate, temperature, and notch stress triaxiality on deformation and fracture are studied. The Arruda-Boyce …
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The Ductile to Brittle Transition in Polycarbonate
… the ductile to brittle failure transition in polycarbonate. The cohesive zone model is motivated by experimental evidence that two different critical energies per unit area of crack growth exist in glassy polymers. A higher energy state is associated with ductile failure (slow crack growth), …
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Accelerated Durability Characterization of Laminated Polycarbonate Systems
… laminates, which often involve sheets made of polycarbonate. This study aims to explore the durability of laminated polycarbonate systems by investigating the interaction of environment and TPU viscoelastic behavior on the time-dependent crack growth in these laminates. The main test utilized …
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Chemical Surface Modification of Polycarbonate to Increase Hydrophilicity
Polycarbonate, commonly used in glasses lenses, is prone to fogging. Fogging can be reduced by modifying the structure of polycarbonate to be more hydrophilic, ideally superhydrophilic with a contact angle less than 10°. Many chemicals were tested to see if they could increase the polarity of …
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Mechanics of Notched Izod impact testing of polycarbonate
Polycarbonate is widely used as a transparent protective material because of its low density and excellent mechanical properties. However, when defects such as cracks or notches are introduced, it is subject to catastrophic brittle failure at relatively low loads. Notched Izod testing is a common …
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Synthesis and characterization of new polycarbonate material systems
Bisphenol A polycarbonate is an engineering thermosplastic which can be utilized for a variety of applications. Modifications to improve upon the properties of this useful material have been attempted since its invention. Three modifications of bisphenol A polycarbonate and its copolymers have been …
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Synthesis and characterization of polycarbonate-polydimethylsiloxane block copolymers
Two methods for the preparation of bisphenol-A polycarbonate-polydimethylsiloxane multi-block or segmented copolymers have been investigated. The first is a solution reaction which utilized the interaction of a preformed, α,ω-dimethylamino terminated polydimethylsiloxane with a preformed, …
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A Study of Crystallization in Bisphenol-A Polycarbonate
The crystallization behavior of bisphenol-A polycarbonate (BAPC) was studied, focusing on the initial stage of crystallization and the secondary stage of crystallization. Bisphenol-A polycarbonate was the polymer chosen for this study because of its slow crystallization rate. With slow …
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Effect of ultraviolet exposure on the durability of polycarbonate
Polycarbonate is commonly used in windshield-canopy structures for military aircraft since it is transparent and possesses excellent toughness characteristics at temperatures well below its glass transition region. It is believed that ultraviolet radiation present in sunlight causes polycarbonate …
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Reversibly Photo-Crosslinkable Polycarbonate-Based Polymersomes for Drug Encapsulation and Delivery
… of polymersomes from poly(ethylene glycol)-block-polycarbonate (PEG-PC) copolymers functionalized with pendant coumarin groups. Coumarin groups undergo photo-reversible dimerization when irradiated with specific ultraviolet wavelengths, so they can be used to prepare polymers with photo-responsive …
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Investigation of factors that influence coloration in polycarbonate based compounded plastics
… Past production data of two low Chroma opaque polycarbonate (PC) plastic grades - PC1 and PC2, were statistically analysed with the aim to quantify the influence on output colour caused by small adjustments in colour formulation made during production. This study revealed that the output colour …
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Characterization of mechanical properties of fused deposition modeling manufactured polycarbonate composites
… characterization of material properties of such polycarbonate composites manufactured by the Fused Deposition Modeling (FDM) method. The approach comprises of tensile testing of FDM manufactured samples following the ASTM D 638-03 and ASTM D 3039-00 standards. This gives the mechanical properties …
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A Novel Process to Create Arbitrary Microcellular Patterns in Polycarbonate using a Laser Beam
… a versatile process to nucleate microcells in polycarbonate sheets via laser beam. This method allows local heating of CO2 saturated polycarbonates which results in the creation of arbitrary shapes of microcellular foamed regions in a plastic part. We present the processing parameters required …
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Crystallization Behavior of Bisphenol-A Polycarbonate: Effects of Crystallization Time, Temperature, and Molar Mass
… and multiple melting behavior of bisphenol-A polycarbonate (PC) was investigated using differential scanning calorimetry (DSC) for the monitoring of thermal behavior and atomic force microscopy (AFM) for the morphology study. The exceedingly slow crystallization kinetics of PC and the …
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