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Showing 1 to 20 of 71 for “"crystallization kinetics"”.
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Crystallization kinetics of lunar composition 15555.
Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy and Materials Science, 1973
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Crystallization Kinetics in Binary Borate Glass Melts
Made available in DSpace on 2014-12-12T00:32:34Z (GMT). No. of bitstreams: 1 7317608.pdf: 7261532 bytes, checksum: a7ac8ba506e0eb918ae19d2398bfebbc (MD5) Previous issue date: 1973
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Crystallization kinetics of polylactide and its blends
… a certain degree of partial miscibility. The crystallization kinetics were investigated on the pure PLA-L and the blends. Two separate studies were conducted, the first on the kinetics of the overall crystallization by means of an Avrami analysis, the second on the growth rates of the …
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Crystallization Kinetics and Phase Behavior of Molecular Solutions
… the effects of the rate of supersaturation on crystallization kinetics and polymorph selectivity; and (ii) to develop a generalized phase diagram from first principles and verify its applicability to a wide range of molecular solutions. This thesis investigates how the rate of supersaturation …
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Crystallization kinetics of polymer melts in extensional flow
A technique to study the kinetics of flow-induced crystallization of polymers in extensional flow has been developed which uses a 4-Roll Mill. The kinetics of a High Density Polyethylene were found to be well described by the Avrami treatment, indicated that the crystallization occurred by sporadic …
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A study of the crystallization kinetics of isotactic polystyrene
… the Lauritzen-Hoffman kinetic theory of polymer crystallization. The primary objectives of the study are to critically test the Lauritzen-Hoffinan theory under conditions not rigorously investigated before and to gain a better understanding of the molecular weight dependence of crystal growth …
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Unrecognized complexities of metamorphism : crystallization kinetics, reaction affinity, and geochronology
… m² s⁻¹ at 600 °C. Limitations in determining crystallization kinetics arise from difficulties in constraining rock-specific properties (e.g., porosity and Al solubility). Ar at the time and location of nucleation is 0.4-5.9 kJ/mol⁻¹ of 12-oxygen garnet ([Delta]T = 4.0-62.0 °C) for the earliest …
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Microstructure Control and Crystallization Kinetics in Amorphous Cadmium-Germanium - Arsenide (Devitrification, Differential Scanning, Calorimetry)
… II-IV-V chalcopyrite semiconductor family. The crystallization of the amorphous form of this compound was investigated using Differential Scanning Calorimetry. The basic operating principles of the two currently most popular DSC instruments (the DuPont 1090 DSC and the Perkin-Elmer DSC7) in the …
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Crystallization Behavior of Bisphenol-A Polycarbonate: Effects of Crystallization Time, Temperature, and Molar Mass
Crystallization 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 …
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Order phenomena in polymer crystallization
… influence of order phenomena in polymer melts on crystallization kinetics has been investigated by means of nuclear magnetic resonance (NMR) spectroscopy. In particular the so-called memory effect in syndiotactic polypropylene (s-PP) and the influence of entangled polymer chains (entanglements) on …
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Chemical processing of lead metatitanate by co-precipitation and sol-gel methods: The role of powder and gel characteristics on crystallization behavior
… evolution of structure on heat treatment, and crystallization. Materials prepared by the two methods were amorphous in the as-prepared state, but transformed to the stable perovskite structure on heat treatment. Crystallization kinetics for the chemically prepared materials were compared with …
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Numerical stimulation of stress-induced crystallization of injection molded semicrystalline thermoplastics
… of sound theoretical models for stress-induced crystallization kinetics in thermoplastics, simulations of the injection molding process of semicrystalline plastics with the consideration of stress-induced crystallization have been scarce. A stress-induced crystallization model for …
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Crystallization Behavior, Tailored Microstructure, and Structure-Property Relationships of Poly(Ether Ketone Ketone) and Polyolefins
… process parameters on semi-crystalline polymer crystallization and final properties. All objectives utilized the advanced characterization technique of fast scanning calorimetry (FSC) using the Mettler Toledo Flash DSC 1. The first half of this work focuses on the high-performance …
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Development and Evaluation of Ternary Amorphous Solid Dispersion of Poorly Water-soluble Compounds
… used polymer screening studies i.e. miscibility, crystallization tendency, Flory-Huggins interaction parameter, solubility parameter, as well as advanced studies (i.e., crystallization kinetics and molecular interaction). Upon selection of the optimum polymer, TASDs were prepared by rotary …
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Chemical and Physical Modifications of Semicrystalline Gels to Achieve Controlled Heterogeneity
… decreased melting point depression, and faster crystallization kinetics. Phase separation between the hydrophilic sulfonated blocks and hydrophobic PEEK blocks, aided by polymer crystallization, resulted in enhanced water uptake, superior proton conductivity, and more closely associated ionic …
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Morphological properties of poly (ethylene terephthalate) (PET) nanocomposites in relation to fracture toughness.
… optical microscopy were used to determine the crystallization effects of MLS addition. Non isothermal crystallization kinetics showed that the melting temperature and crystallization temperature decrease as the MLS percent increases. This delayed crystallization along with the irregular …
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Synthetic Design of Multiphase Systems for Advanced Polymeric Materials
… blocky halogenation of PEEK provides faster crystallization kinetics, higher glass transition (Tg) and melting temperatures as well as superior crystallizability than random halogenation. When comparing halogen identity, increasing halogen size results in increased Tgs, decreased backbone …
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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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Phase transitions of poly (l-lactic acid) in bulk and in solution
… adopted as the primary experimental techniques. Crystallization during annealing and drawing in melt-spun PLLA fibers is studied by WAXS with a quantitative evaluation of crystallinity and orientation. This represents the study of phase transitions of PLLA in bulk at temperatures above glass …
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Crystallization, Morphology, Thermal Stability and Adhesive Properties of Novel High Performance Semicrystalline Polyimides
… ability to crystallize from the melt; (c) fast crystallization kinetics and (d) melt processability. This unique combination of properties is presently unavailable in any other polyimide. In this regard, the present work investigates the crystallization, morphology and thermal stability of two …
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