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Showing 1 to 16 of 16 for “"Lamellar Thickness"”.
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Structure-Property Relationships: Model Studies on Melt Extruded Uniaxially Oriented High Density Polyethylene Films Having Well Defined Morphologies
… films having simple and well-defined stacked lamellar morphology, either with or without a distinct presence of row-nucleated fibril structures, have been utilized as <i>model</i> materials to carry out investigations on solid state structure-property relationships. Four different subjects …
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A Study of Crystallization in Bisphenol-A Polycarbonate
… crystallization dealt with the isothermal lamellar thickening of BAPC crystals during annealing, after crystallization for an extended period of time. Small-angle X-ray scattering and differential scanning calorimetry experiments were performed on bisphenol-A polycarbonate samples …
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Cell dynamical system approach to block copolymers
… the correct exponent for the block copolymer lamellar thickness.
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On the Melting and Crystallization of Linear Polyethylene, Poly(ethylene oxide) and Metallocene Linear Low-Density Polyethylene
… method was also examined using initial lamellar thickness literature data for a linear polyethylene fraction at different crystallization temperatures. The equilibrium melting temperature obtained by the Gibbs-Thomson approach and the C2 value extracted from the initial lamellar …
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Crystallization and melting behavior of (ε-caprolactone)-based homopolymer and triblock copolymer
… inverse relation between undercooling and the lamellar thickness. Claims have appeared in the literature that analysis of growth rate data using the LH theory does not yield physically meaningful parameters. This work will show that the lateral and fold interfacial free energy parameters, σ and …
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Evaluating the Time-Dependent Melting Behavior of Semicrystalline Polymers Through Strobl's 3-Phase Model
… using the correlation function confirms that the lamellar thickness increases with crystallization temperature and is independent of time. The spread between equilibrium melting and crystallization temperatures determined in this work (Tfâ"" = 533K, Tcâ"" = 544K) is much smaller than reported by …
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Crystallization Behavior of Bisphenol-A Polycarbonate: Effects of Crystallization Time, Temperature, and Molar Mass
… morphological studies using AFM showed that mean lamellar thickness increases with time during isothermal annealing. These results are discussed in light of isothermal thickening of lamellar crystals. Lastly, almost 200 DSC melting traces of varying molar mass PC samples thermally treated under …
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Design and Characterization of Central Functionalized Asymmetric tri-Block Copolymer Modified Surfaces
… confirm the CFABC polymer brush structures and thickness. The surface properties of CFABC polymer brush modified silicon wafer substrates subjected to different environmental parameters were studied. Reversibly switchable surface energies were observed when the polymer brush modified surfaces …
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Equilibrium Melting Temperature Determination of Semicrystalline Polymers through Nonlinear Hoffman-Weeks Extrapolation and Secondary Crystallization of Ethylene/Styrene Copolymers
… and poly(ethylene oxide). The predicted initial lamellar thickness as a function of the crystallization temperature matches well with experimental results and/or literature values. Results based on the nonlinear HW analysis are consistent with those obtained from the analysis of the temperature …
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Effect of chain structure on the thermodynamics and kinetics of polymer crystallization
… theory was that it predicted divergence of the lamellar thickness and crystal growth rate at finite undercoolings - the so-called “δ𝑙 catastrophe." Within this work, it has been shown that the "δ𝑙 catastrophe" can be eliminated by considering all of the implications of the Hoffman-Miller …
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Understanding the Mechanisms of Shock-Induced Deformation in Polymeric Systems
… is shown to be a non-monotonic function of lamellar thickness and crystallinity fraction, and they each contribute to shock energy storage. The computational study of ethanol reveals the configurational and vibrational changes undergone by the liquid in response to elevated shock pressure …
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Application of Diagnostic Methods to Assess Ageing Processes in Polymers
… some specimens. Elastic moduli calculated from lamellar thickness, static tensile tests, dynamic mechanical analysis, and acoustic spectroscopy suggested that a difference could be drawn between aged and unaged specimens, in which elastic moduli generally increased with exposure to ageing …
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Crystalline Morphologies of Poly(butadiene)-b-Poly(ethylene oxide) Block Copolymers in n-Heptane
… at a high PEO composition which reduced the lamellar thickness of the crystals. The competition between the PEO core crystallization and the aggregation of the micellar units leads to coexistence regions of lamellae with platelets and cylinders with platelets. The novelty of this thesis …
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Crystallization and structure-property investigations of semicrystalline poly(arylene ether) based polymers
… have been attributed to differences in film thickness; the causes behind such effects, however, still remain unclear. The second part of this dissertation involves the study of a series of high performance polyimides. Semicrystalline polyimides based on an all para-linked diamine, …
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Phase Behavior and Phase Separation Kinetics in Polymer Solutions under High Pressure
… were attributed to the presence of different lamellar thickness that are formed in the crystallization, final depressurization and sample collection stages. Depending upon the crystallization path some differences were noted. The crystals formed by first going through L-L phase separation …
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Self-Consistency of the Lauritzen-Hoffman and Strobl Models of Polymer Crystallization Evaluated for Poly(ε-caprolactone) Fractions and Effect of Composition on the Phenomenon of Concurrent Crystallization in Polyethylene Blends
… using this Porod constant yielded the values of lamellar crystal thickness, which were similar to these estimated using the Hosemann-Bagchi Paracrystalline Lattice model. The temperature dependence of the lamellar crystal thickness was consistent with both LH and the Strobl model of polymer …