Chemical Engineering Commons^™

Molecular Structure Of Polystyrene At Air/Polymer And Solid/Polymer Interfaces, K. S. Gautam, Alexander D. Schwab, Ali Dhinojwala, D. Zhang, S. M. Dougal, M. S. Yeganeh

College of Polymer Science and Polymer Engineering

IR-visible sum-frequency generation(SFG) spectroscopy has been used in a total internal reflection geometry to study the molecular structure of polystyrene (PS) at PS/sapphire and PS/air interfaces, simultaneously. The symmetric vibrational modes of the phenyl rings dominate the SFG spectra at the PS/air interface as compared to the antisymmetric vibrational modes at the PS/sapphire interface. This indicates approximately parallel orientation of the phenyl rings at the PS/air interface while nearly perpendicular orientation at the PS/sapphire interface, with respect to the surface normal.

Theoretical Investigation On Dynamics Of Photopolymerization-Induced Phase Separation And Morphology Development In Nematic Liquid Crystal/Polymer Mixtures, Domasius Nwabunma, Hao-Wen Chiu, Thein Kyu

College of Polymer Science and Polymer Engineering

A theoretical investigation of the dynamics of photopolymerization-induced phase separation (PIPS) and morphology development in a nematic liquid crystal (LC) polymer network mixture has been undertaken by incorporating photopolymerization kinetics into the coupled time-dependent Ginzburg-Landau (TDGL-Model C) equations. The simulation on the spatio-temporal evolution of the coupled LC concentration and orientation order parameters reveals that both morphological and scattering patterns for the orientation order parameter initially lag behind those of the concentration order parameter. However, the two fields evolve to the same spatial topologies with the progression of time. The PIPS dynamics is characterized only by the late stage of …

Bending Instability Of Electrically Charged Liquid Jets Of Polymer Solutions In Electrospinning, Darrell Hyson Reneker, Alexander L. Yarin, Hao Fong, Sureeporn Koombhongse

College of Polymer Science and Polymer Engineering

Nanofibers of polymers were electrospun by creating an electrically charged jet of polymer solution at a pendent droplet. After the jet flowed away from the droplet in a nearly straight line, it bent into a complex path and other changes in shape occurred, during which electrical forces stretched and thinned it by very large ratios. After the solvent evaporated, birefringent nanofibers were left. In this article the reasons for the instability are analyzed and explained using a mathematical model. The rheological complexity of the polymer solution is included, which allows consideration of viscoelastic jets. It is shown that the longitudinal …

Spatiotemporal Growth Of Faceted And Curved Single Crystals, Thein Kyu, Rujul Mehta, Hao-Wen Chiu

College of Polymer Science and Polymer Engineering

The spatiotemporal growth of single crystals in a crystalline polymer has been investigated theoretically based on a nonconserved time dependent Ginzburg-Landau equation (known as TDGL model A). In the description of the total free energy, a double-well local foe energy density signifying metastability of crystal ordering is combined with a nonlocal free energy term representing an interface gradient. The resulting nonlinear reaction diffusion equation after renormalization possesses a solitary wave property. Two-dimensional numerical calculations were performed to elucidate the faceted single crystal growth including square, rectangular, diamond-shaped, and curved single crystals. A three-dimensional simulation was also undertaken for the emergence …

In-Situ Frequency-Dependent Electromagnetic Sensing For Monitoring Physical And Chemical Attributes During Chemical Processing, Jeffrey David Rogozinski

Dissertations, Theses, and Masters Projects

The objective of this research was to develop an in-situ sensing technique that monitors the molecular-level response of ions and dipoles to an applied electric field in order to characterize the changes in state of a polymer resin during chemical processing. This technique needs to be capable of monitoring the reaction progress not only in the laboratory setting but also in-situ in the processing tool or reaction environment. Frequency Dependent Electromagnetic Sensing (FDEMS) was selected for this task.;This dissertation investigates the applicability of FDEMS to monitoring two types of processing methods: reactive and batch reactor. The reactive processing system examined …

The Dehydrochlorination Mechanism Of The Internal Allylic Chloride Structure In Poly(Vinyl Chloride), Lynda B. Payne

Dissertations, Theses, and Masters Projects

No abstract provided.

A Study Of The Aging Of Polyamide-11 Based On Molecular Weight Measurements, Yao Lin

Dissertations, Theses, and Masters Projects

No abstract provided.

Blending Of Immiscible Polymers In A Mixing Zone Of A Twin Screw Extruder- Effects Of Compatibilization, William Macknight, O. Franzheim, T. Rische, M. Stephan

William MacKnight

Miscibility And Characterization Of The Ternary Crystalline System: Poly(Vinyl Butyral)/Poly(Vinyl Alcohol)/Nylon6, William Macknight, H. Jeong, M. Rooney, D. J. David, F. E. Karasz, T. Kajiyama

William MacKnight

No abstract provided.

Miscibility Of Polyvinyl Butyral/Nylon 6 Blends, William Macknight, H. Jeong, M. Rooney, D. J. David, F. E. Karasz, T. Kajiyama

William MacKnight

No abstract provided.