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Full-Text Articles in Engineering
Effects Of Molecular Architecture On Crystallization Behavior Of Pol(Lactic Acid) And Ethylene-Vinyl Acetate, Jeffrey Paul Kalish
Effects Of Molecular Architecture On Crystallization Behavior Of Pol(Lactic Acid) And Ethylene-Vinyl Acetate, Jeffrey Paul Kalish
Open Access Dissertations
The relationship between polymer chain architecture, crystallization behavior, and morphology formation was investigated. The structures formed are highly dependent on chain configuration and crystallization kinetics. Poly(lactic acid) (PLA) and Poly(ethylene-co-vinyl acetate) (EVA) random copolymers were studied. Sample characterization was performed using a variety of techniques, including spectroscopy, scattering, and calorimetry. In PLA, structural differences between α’ and α crystalline phases were analyzed using cryogenic infrared and Raman spectroscopy. Compared to the crystal, the ’ crystal has slightly looser packing and weaker intermolecular interactions involving carbonyl and methyl functional groups. Simulations in conjunction with Raman scattering analyzed the …
Structure-Property Evolution During Polymer Crystallization, Deepak Arora
Structure-Property Evolution During Polymer Crystallization, Deepak Arora
Open Access Dissertations
The main theme of this research is to understand the structure-property evolution during crystallization of a semicrystalline thermoplastic polymer. A combination of techniques including rheology, small angle light scattering, differential scanning calorimetry and optical microscopy are applied to follow the mechanical and optical properties along with crystallinity and the morphology. Isothermal crystallization experiments on isotactic poly-1-butene at early stages of spherulite growth provide quantitative information about nucleation density, volume fraction of spherulites and their crystallinity, and the mechanism of connecting into a sample spanning structure. Optical microscopy near the fluid-to-solid transition suggests that the transition, as determined by time-resolved mechanical …