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Georgia Tech
1.
Kasturirangan, Anupama.
Specific interactions in carbon dioxide + polymer systems.
Degree: PhD, Chemical and Biomolecular Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/22570 
► Specific Interactions in Carbon Dioxide + Polymer Systems Anupama Kasturirangan 163 Pages Directed by Dr. Amyn S. Teja Weak complex formation in CO2 + polymer…
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▼ Specific Interactions in Carbon Dioxide + Polymer Systems
Anupama Kasturirangan
163 Pages
Directed by
Dr. Amyn S. Teja
Weak complex formation in CO2 + polymer and CO2 + copolymer systems containing C=O and C-F groups was quantified using in situ FTIR spectroscopy. The enthalpy of interaction thus obtained was directly incorporated into a lattice model and compressibility effects were accounted for via ratio of free volumes in modified segment number. CO2 + fluropolymer phase behavior could be correlated within experimental error (AAD of about 2%) using the new model, a task that has been beyond the capability of published models and it was also possible to predict phase equilibria of CO2 + PLGA copolymer systems with a single parameter obtained by fitting cloud point behavior in a reference system (CO2 + PLA in this case).New data on sorption equilibria in several CO2 + PLGA systems were obtained using a quartz crystal microbalance (QCM) and new data on Tg depression in the CO2 + PLA system were also obtained using a high pressure DSC method and used to demonstarte that model parameters are valid over extended pressure ranges. The new compressible lattice model developed is thus able to correlate cloud points, sorption equilibria, glass transition temperatures, and melting points using a single parameter. The model is therefore likely to be beneficial in many applications involving CO2 + polymer systems including drug delivery and encapsulation, polymer coating, and membranes for natural gas separations.
Advisors/Committee Members: Dr Amyn.S.Teja (Committee Chair), Dr Haskell Beckham (Committee Member), Dr Peter. J. Ludovice (Committee Member), J.Koros%22%29&pagesize-30">
Dr William.
J.Koros (Committee Member),
Dr. Thomas H. Sanders (Committee Member).
Subjects/Keywords: Polymer solutions; Lewis acid-base complex; Phase equilibria; CO₂ assisted polymer processing; Carbon dioxide; Polymers; Fourier transform infrared spectroscopy; Mathematical models
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APA (6th Edition):
Kasturirangan, A. (2008). Specific interactions in carbon dioxide + polymer systems. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/22570
Chicago Manual of Style (16th Edition):
Kasturirangan, Anupama. “Specific interactions in carbon dioxide + polymer systems.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021.
http://hdl.handle.net/1853/22570.
MLA Handbook (7th Edition):
Kasturirangan, Anupama. “Specific interactions in carbon dioxide + polymer systems.” 2008. Web. 16 Jan 2021.
Vancouver:
Kasturirangan A. Specific interactions in carbon dioxide + polymer systems. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 16].
Available from: http://hdl.handle.net/1853/22570.
Council of Science Editors:
Kasturirangan A. Specific interactions in carbon dioxide + polymer systems. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/22570
Georgia Tech
2.
Singh, Lovejeet.
Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films.
Degree: PhD, Chemical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/4822
► The behavior of polymeric systems confined into thin films is a situation that has numerous practical consequences. One particular application in which the properties of…
(more)
▼ The behavior of polymeric systems confined into thin films is a situation that has numerous practical consequences. One particular application in which the properties of thin polymer films is becoming crucially important is in the design, formulation, and processing of photoresists for semiconductor microlithography. As devices continue to be scaled down into the nano-regime, the microelectronics industry will ultimately rely upon a molecular understanding of materials for process development. The majority of these devices are now confined in planar geometries; thus, thin films have played an ever-increasing role in manufacturing of modern electronic devices. This movement towards thinner resist films creates larger surface to volume ratios, and hence thin films can exhibit thermodynamic, structural, and dynamic properties that are different from those of the bulk material. It is thus extremely important to understand the properties of polymers when confined in such geometries for various applications including resists for lithographic patterning. In present work, the influence of a variety of factors including film thickness, molecular weight, and substrate interactions on the polymer thin film physical properties such as the glass transition temperature, coefficient of thermal expansion, dissolution rate, and diffusion coefficient was studied in detail using a combination of experimental characterization and molecular modeling simulation techniques.
Advisors/Committee Members: Dr. Clifford L. Henderson (Committee Chair), Dr. Peter J. Ludovice (Committee Co-Chair), Dr. Carson J. Meredith (Committee Member), Dr. Laren Tolbert (Committee Member), Dr. William J. Koros (Committee Member).
Subjects/Keywords: Diffusion coefficient; Glass transition temperature; Polymer thin films; Thin films; Polymers; Glass transition temperature; Diffusion
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APA ·
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APA (6th Edition):
Singh, L. (2004). Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4822
Chicago Manual of Style (16th Edition):
Singh, Lovejeet. “Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021.
http://hdl.handle.net/1853/4822.
MLA Handbook (7th Edition):
Singh, Lovejeet. “Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films.” 2004. Web. 16 Jan 2021.
Vancouver:
Singh L. Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 16].
Available from: http://hdl.handle.net/1853/4822.
Council of Science Editors:
Singh L. Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4822
Georgia Tech
3.
Ozkan, Ibrahim Ali.
Thermodynamic model for associating polymer solutions.
Degree: PhD, Chemical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5115
► Polymer solutions in which there are strong specific interactions between the polymer and the solvent are of interest in a number of biological applications. Of…
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▼ Polymer solutions in which there are strong specific interactions between the polymer and the solvent are of interest in a number of biological applications. Of particular interest are polymer solutions in which supercritical carbon dioxide (CO2) is the solvent, because polymer processing with CO2 is an important application of green chemistry. Unfortunately, experimental data on the phase behavior of polymer - CO2 systems are relatively scarce, as are models that describe the phase behavior of such systems. The focus of this research is therefore on developing a thermodynamic model based on lattice theory for calculating phase behavior of high pressure polymer solutions with specific intermolecular interactions.
A new model, termed the LELAC (Lattice-based Extended Liquid Activity Coefficient) model is proposed based on the gART-L model of Sukhadia and Variankaval. The new model incorporates the compressibility effect at high pressures. The parameters of the model are (1) the equilibrium constant for association between a polymer segment and a solvent, (2) the specific interaction energy between a polymer segment and a solvent, and (3) the dispersion interaction energy. The dispersion interaction energy is calculated using Regular Solution Theory and therefore depends on the pure component properties. One or both of the remaining parameters is obtained from independent measurements such as FT- IR spectra. Alternatively, the two parameters can be obtained by fitting data.
Cloud point curves of polymer - CO2 systems have been successfully correlated (1.3 % error) with the new model. Also, using fitted parameters from cloud point data, the sorption behavior of CO2 in polymers has been predicted. The polymer investigated include PBMA, PVAc and Polyacrylates. Comparison of cloud points with those obtained using the SAFT model revealed that the new model performs better than the SAFT model (3.6% error) with two adjustable parameters.
The use of FT-IR to investigate interactions between CO2 and a number of polymers has been studied. The results confirm that complexes are formed between CO2 and PMMA, PEMA, PBMA, PVMK, and PVAc. A complex of PVC and CO2 is reported and a new mechanism involving a carbon oxygen triple bond is postulated for this system.
Advisors/Committee Members: Dr. Amyn S. Teja (Committee Chair), Dr. J. Carson Meredith (Committee Member), Dr. Peter J. Ludovice (Committee Member), Dr. Thomas H. Sanders (Committee Member), Dr. William J. Koros (Committee Member).
Subjects/Keywords: Modeling; Association; Polymer solutions; Thermodynamics; Thermochemistry; Polymer solutions; Chemical models
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APA ·
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APA (6th Edition):
Ozkan, I. A. (2004). Thermodynamic model for associating polymer solutions. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5115
Chicago Manual of Style (16th Edition):
Ozkan, Ibrahim Ali. “Thermodynamic model for associating polymer solutions.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021.
http://hdl.handle.net/1853/5115.
MLA Handbook (7th Edition):
Ozkan, Ibrahim Ali. “Thermodynamic model for associating polymer solutions.” 2004. Web. 16 Jan 2021.
Vancouver:
Ozkan IA. Thermodynamic model for associating polymer solutions. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 16].
Available from: http://hdl.handle.net/1853/5115.
Council of Science Editors:
Ozkan IA. Thermodynamic model for associating polymer solutions. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5115
Georgia Tech
4.
Marla, Krishna Tej.
Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces.
Degree: PhD, Chemical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/7604
► Nanoscale colloidal particles display fascinating electronic, optical and reinforcement properties as a consequence of their dimensions. Stable dispersions of nanoscale colloids find applications in drug…
(more)
▼ Nanoscale colloidal particles display fascinating electronic, optical and reinforcement properties as a consequence of their dimensions. Stable dispersions of nanoscale colloids find applications in drug delivery, biodiagnostics, photonic and electronic devices, and polymer nanocomposites. Most nanoparticles are unstable in dispersions and polymeric surfactants are added generally to improve dispersability and control self-assembly. However, the effect of polymeric modifiers on nanocolloid properties is poorly understood and design of modifiers is guided usually by empirical approaches. Monte Carlo simulations are used to gain a fundamental molecular-level understanding of the effect of modifiers properties on the thermodynamics and interaction forces of nanoscale colloidal particles. A novel method based on the expanded ensemble Monte Carlo technique has been developed for calculation of the chemical potential of colloidal particles in colloid-polymer mixtures (CPM). Using this method, the effect of molecular parameters like colloid diameter, polymer chain length, colloid-polymer interaction strength, and colloid and polymer concentrations, on the colloid chemical potential is investigated for both hard-sphere and attractive Lennard-Jones CPM. The presence of short-chain polymeric modifiers reduces the colloid chemical potential in attractive as well as athermal systems. In attractive CPM, there is a strong correlation between polymer adsorption and colloid chemical potential, as both show a similar dependence on the polymer molecular weight. Based on the simulation results, simple scaling relationships are proposed that capture the functional dependence of the thermodynamic properties on the molecular parameters. The polymer-induced interaction forces between the nanoparticles have been calculated as a function of the above parameters for freely-adsorbing and end-grafted homopolymer modifiers. The polymer-induced force profiles are used to identify design criteria for effective modifiers. Adsorbing modifiers give rise to attractive interactions between the nanoparticles over the whole parameter range explored in this study. Grafted surface modifiers lead to attraction or repulsion based on the polymer chain length and grafting density. The polymer-induced attraction in both adsorbing and grafted modifiers is attributed primarily to polymer intersegmental interactions and bridging. The location of the thermodynamic minimum corresponding to the equilibrium particle spacing in nanoparticle-polymer mixtures can be controlled by tuning the modifier properties.
Advisors/Committee Members: Dr. J. Carson Meredith (Committee Chair), Dr. Charles A. Eckert (Committee Member), Dr. Clifford L. Henderson (Committee Member), Dr. Peter J. Ludovice (Committee Member), Dr. Rigoberto Hernandez (Committee Member).
Subjects/Keywords: Nanoparticle interaction forces; Colloid chemical potential; Nanoparticle-polymer systems; Colloid-polymer mixtures
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APA ·
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CSE |
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APA (6th Edition):
Marla, K. T. (2004). Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7604
Chicago Manual of Style (16th Edition):
Marla, Krishna Tej. “Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021.
http://hdl.handle.net/1853/7604.
MLA Handbook (7th Edition):
Marla, Krishna Tej. “Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces.” 2004. Web. 16 Jan 2021.
Vancouver:
Marla KT. Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 16].
Available from: http://hdl.handle.net/1853/7604.
Council of Science Editors:
Marla KT. Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/7604
Georgia Tech
5.
Sormana, Joe-Lahai.
Combinatorial Synthesis and High-Throughput Characterization of Polyurethaneureas and Their Nanocomposites with Laponite.
Degree: PhD, Chemical Engineering, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/11640
► Segmented polyurethaneureas (SPUU) are thermoplastic elastomers with excellent elastic properties, high abrasion resistance and tear strength, making them very useful in numerous industrial applications ranging…
(more)
▼ Segmented polyurethaneureas (SPUU) are thermoplastic elastomers with excellent elastic properties, high abrasion resistance and tear strength, making them very useful in numerous industrial applications ranging from microelectronics (slurry pad) to biomedical (artificial heart vessels) applications. The elastic and mechanical properties of these materials are strongly influenced by their two phase morphology. The factors that influence phase separation include difference in polarity between the hard and soft phases, composition and temperature. In general good phase separation results in materials with superior mechanical and elastic properties. Due to the immense potential applications of SPUU elastomers, there is a need for materials with higher strength. However, higher strength is not desired at the detriment of elasticity. If fact, stronger materials with enhanced elasticity are desired. In this thesis, high-strength SPUU elastomers were synthesized by incorporating reactive Laponite particles with surface-active free amine. The synthesis of pure SPUU is very complex, and addition of a reactive silicate further increases the complexity. To remedy this challenge, combinatorial methods and high-throughput screening techniques were used to optimize the diamine concentration and cure temperature. It was determined that pure SPUU elastomers prepared at a diamine stoichiometry of 85 100 mole %, and cured at 90 95 °C produced materials with higher strength and elongation at break. SPUU nanocomposites were prepared by maintaining the overall diamine stoichiometry at 95 mole %, and cured at 90 °C. Uniaxial tensile strength was optimized at a particle weight fraction of 1 wt. %, with a nearly 200 % increase in tensile strength and a 40 % increase in elongation at break, compared to pristine SPUU.
Advisors/Committee Members: Dr. J. Carson Meredith (Committee Chair), Dr. F. Joseph Schork (Committee Member), Dr. Mohan Srinivasarao (Committee Member), Dr. Peter J. Ludovice (Committee Member), Dr. William J. Koros (Committee Member).
Subjects/Keywords: Combinatorial; High throughput; Polyurethaneurea; Mechanical properties; Combinatorial analysis; Elastomers; Elastoplasticity; Materials science; Polyurethanes; Nanocomposites
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APA ·
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MLA ·
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CSE |
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APA (6th Edition):
Sormana, J. (2005). Combinatorial Synthesis and High-Throughput Characterization of Polyurethaneureas and Their Nanocomposites with Laponite. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/11640
Chicago Manual of Style (16th Edition):
Sormana, Joe-Lahai. “Combinatorial Synthesis and High-Throughput Characterization of Polyurethaneureas and Their Nanocomposites with Laponite.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021.
http://hdl.handle.net/1853/11640.
MLA Handbook (7th Edition):
Sormana, Joe-Lahai. “Combinatorial Synthesis and High-Throughput Characterization of Polyurethaneureas and Their Nanocomposites with Laponite.” 2005. Web. 16 Jan 2021.
Vancouver:
Sormana J. Combinatorial Synthesis and High-Throughput Characterization of Polyurethaneureas and Their Nanocomposites with Laponite. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 16].
Available from: http://hdl.handle.net/1853/11640.
Council of Science Editors:
Sormana J. Combinatorial Synthesis and High-Throughput Characterization of Polyurethaneureas and Their Nanocomposites with Laponite. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/11640
. 
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