DOCSLIB.ORG

Pollutants in Clay Montmorillonite

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Pollutants in Clay Montmorillonite Loyola University Chicago Loyola eCommons Dissertations Theses and Dissertations 1997 The Computational Study of "Model" Pollutants in Clay Montmorillonite Sung-Ho Park Loyola University Chicago Follow this and additional works at: https://ecommons.luc.edu/luc_diss Part of the Chemistry Commons Recommended Citation Park, Sung-Ho, "The Computational Study of "Model" Pollutants in Clay Montmorillonite" (1997). Dissertations. 3720. https://ecommons.luc.edu/luc_diss/3720 This Dissertation is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Dissertations by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 1997 Sung-Ho Park LOYOLA UNIVERSITY CHICAGO THE COMPUTATIONAL STUDY OF "MODEL" POLLUTANTS IN CLAY MONTMORILLONITE A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY BY SUNG-HO PARK CHICAGO, ILLINOIS MAY, 1997 Copyright by Sung-Ho Park 1997 All rights reserved. ACKNOWLEDGMENTS There are so many people who I would like to thank for my study at Loyola. First I would like to thank my advisor, Dr. Alanah Fitch for her sincere guidance. She supported in every way from answering questions to financial support. I also learned a lot from her in reading articles, summarizing ideas, and so on. She is an excellent reader, scientific writer, professor, and play writer. I am sometimes amazed by how much she really can work within a limited time. I also would like to express thanks to all my committee members. Professor Kenneth Olsen answered questions regarding molecular dynamics simulations. I also learned broad utility of molecular dynamics simulations from his course. He also allowed me to use all the departmental workstations as well as my old friend Indigo, and it really helped me when I had to run several calculations at the last minute. I also would like to thank Professor Albert Hedinger who I needed to see to get answers for the inorganic questions. He pointed out that not only the chemical probes in my study are inorganic but also clay itself is inorganic. You were absolutely right and I had to understand a lot of inorganic chemistry for the correct considerations in modeling. I would like to thank Professor Willetta Greene-Johnson who also is a physical chemist with a lot of background in surface chemistry and computational studies. She lll recommended that I wait until I got a complete package of software for the simulations instead of making my own codes for the problem. You were definitely right and I acquired a good computational package from MSI/Biosym thereafter. I also would like to express special thanks to Professor George Schatz at Northwestern University. He served as an outside committee member and was kind enough to help me in several meetings. I am also indebted to the people in our group including Sean Mellican, Sue Macha, Yunlong Wang, Simona Dragun, Scott Baker, Joe Lohr, and other former group members. I enjoyed working in our group due to their kindness and friendship. I would like to thank greatly to my parents in Korea. They were so much supportive in many ways that all of my achievements came from them. My sisters, Sung-Hee and Sung-Jee have been supportive and I thank them, too. During the entire course of study, my wife Yoo-Hee has been cheering me up by playing the piano and by being a nice friend during the ups and downs. I thank you a lot, too. My sons, Peter and Daniel were also helpful simply by showing their lovely faces in front of me. Peter recently told me that he liked to be either a chemist or a medical doctor. I believe that you will need a lot of chemistry and I hope I will be helpful at the time when you need assistance. Chicago is a wonderful city in terms of many different things. Especially, I enjoyed listening to WMBI (Moody Bible Institute radio) every time I drive back and IV forth between my home and the lab. I believe their programs and gospel music help my spiritual health during the study. Therefore, I also thank the people at Moody Bible. Finally, I would like to express my greatest thanks to the God. He knows all the chemistry and physics from alpha to omega and created me, studying chemistry! v CONTENTS ACKNOWLEDGMENTS .................................................................................................... iii LIST OF TABLES .............................................................................................................. xii LIST OF FIGURES .......................................................................................................... xiv LIST OF SCHEMES ........................................................................................................................... xvii LIST OF ABBREVIATIONS ........................................................................................... xviii ABSTRACT ........................................................................................................................ xx Chapter I. CLAY AND CLAY MINERALS .................................................................................. 1 A. Background ............................................................................................................. 1 1. Contents of Clay ............................................................................................... 1 a. Clay, the Definition ................................................................................... 1 b. Formation of Clay; The Difference From Soils ........................................ 1 c. Structure of Clay Minerals ........................................................................ 2 d. What is the Classification of Clay Minerals I Phyllosilicates? ................. 3 2. Properties of Clay ............................................................................................. 7 a. Cationic Exchange ..................................................................................... 7 b. Colloidal Property ..................................................................................... 7 c. Water-clay Swelling ................................................................................. 8 vi 3. Environments and Clay .................................................................................... 9 B. Experimental Studies of Clay Adsorption ............................................................. 11 C. Clay Adsorption Modeling ................................................................................... 13 1. Introduction .................................................................................................... 13 2. Basic (General) Modeling .............................................................................. 14 3. Monte Carlo Simulations on Clay Modeling ................................................. 16 4. Molecular Mechanics/Molecular Dynamics on Clay Modeling ..................... 19 II. CLAY-MODIFIED ELECTRODE (CME) ................................................................. 22 A. Introduction .......................................................................................................... 22 B. Immobilization of Clay on Electrodes .................................................................. 24 C. Diffusional Transport Study with CME and This Study ...................................... 27 1. Introduction .................................................................................................... 27 2. Cyclic Voltammetry ....................................................................................... 29 3. Diffusion Information From Clay-modified Electrode .................................. 33 4. Intermolecular Differences in Diffusive Probes ............................................. 36 III. COMPUTATIONAL CHEMISTRY ........................................................................... 38 A. History ................................................................................................................... 38 B. Application of Computer Simulations in Liquids ................................................. 42 1. Introduction .................................................................................................... 42 2. Monte Carlo Simulation (MC) ....................................................................... 43 3. Molecular Dynamics Simulation (MD) .......................................................... 46 vii N. QUANTUM MECHANICAL ELECTRONIC STRUCTURE METHODS (MOLECULAR ORBIT AL CALCULATIONS) ........................................................ 50 A. Introduction ........................................................................................................... 50 B. Restricted Hartree-Fock vs. Unrestricted Hartree-Fock ........................................ 55 C. Atomic Charges ..................................................................................................... 59 D. Frontier Molecular Orbital Theory ........................................................................ 60 V. MOLECULAR MECHANICS AND MOLECULAR DYNAMICS .......................... 63 A. Introduction; Atomic Motions in a Molecule From One Conformation to Another ............................................................................... 63 B. Forcefield, the Basis of the Evaluation
Load more

Recommended publications
  • Hectorite: Synthesis, Modification, Assembly and Applications Jing Zhang, Chun Hui Zhou, Sabine Petit, Hao Zhang
    Hectorite: Synthesis, modification, assembly and applications Jing Zhang, Chun Hui Zhou, Sabine Petit, Hao Zhang To cite this version: Jing Zhang, Chun Hui Zhou, Sabine Petit, Hao Zhang. Hectorite: Synthesis, modification, assembly and applications. Applied Clay Science, Elsevier, 2019, 177, pp.114-138. 10.1016/j.clay.2019.05.001. hal-02363196 HAL Id: hal-02363196 https://hal-cnrs.archives-ouvertes.fr/hal-02363196 Submitted on 2 Dec 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 1 Hectorite：Synthesis, Modification, Assembly and Applications 2 3 Jing Zhanga, Chun Hui Zhoua,b,c*, Sabine Petitd, Hao Zhanga 4 5 a Research Group for Advanced Materials & Sustainable Catalysis (AMSC), State Key Laboratory 6 Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang 7 University of Technology, Hangzhou 310032, China 8 b Key Laboratory of Clay Minerals of Ministry of Land and Resources of the People's Republic of 9 China, Engineering Research Center of Non-metallic Minerals of Zhejiang Province, Zhejiang Institute 10 of Geology and Mineral Resource, Hangzhou 310007, China 11 c Qing Yang Institute for Industrial Minerals, You Hua, Qing Yang, Chi Zhou 242804, China 12 d Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), UMR 7285 CNRS, Université de 13 Poitiers, Poitiers Cedex 9, France 14 15 Correspondence to: Prof.
    [Show full text]
  • Reactions Accompanying Stabilization of Clay with Cement A
    Reactions Accompanying Stabilization Of Clay with Cement A. HERZOG, Senior Lecturer in Civil Engineering, University of New South Wales, Newcastle, Australia, and J. K. :MITCHELL, Assistant Professor of Civil Engineering, and Assistant Research Engineer, Institute of Transportation and Traffic Engineering, University of California, Berkeley This paper reports the results of an investigation aimed at de­ lineating the nature of the reactions accompanying the stabili­ zation of clay with portland cement. Consideration of the nature of cement hydration, the physico-chemical character­ istics of clays and lime-clay interaction leads to the hypothesis that during the hydration of a clay-cement mixture, hydrolysis and hydration of cement could be regarded as primary reac­ tions which form usual cement hydration products, increase the pH, and liberate lime. The high pH and Ca(OHh concen­ tration could initiate attack of the clay particles and also cause breakdown of amorphous silica and alumina which then could combine with calcium to form secondary cementitious material. A clay-cement skeleton and a clay matrix are likely. Mechanical, X-ray diffraction, and chemical tests on kao­ linite and montmorillonite stabilized with portland cement and with pure tricalcium silicate (C3S), the major strength-producing compound in portland cement, gave results in agreement with this hypothesis. Compacted clay-cement mixtures were cured at 100 percent relative humidity and at 60 C (to accelerate hardening) and studied at different times after molding. X-ray analyses showed that calcium hydroxide was formed in hydrat­ ing clay-cement, but was rapidly used up in reaction with the clay. Minor alteration of the kaolinite-cement X-ray pattern and marked alteration of the montmorillonite-cement X-ray pattern were indicated after curing periods of 12 weeks, sug­ gesting clay mineral structure breakdown and/or interaction with cement at particle surfaces.
    [Show full text]
  • Storylines in Intercalation Chemistry
    Dalton Transactions Storylines in intercalation chemistry Journal: Dalton Transactions Manuscript ID: DT-ART-01-2014-000203.R2 Article Type: Perspective Date Submitted by the Author: 07-May-2014 Complete List of Authors: Lerf , Prof. Dr. Anton; Walther-Meissner-Institut,D-85748 Garching, der Bayerischen Akademie der Wissenschaften Page 1 of 33 Dalton Transactions Storylines in intercalation chemistry A. Lerf Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching Abstract Intercalation chemistry is soon hundred years old. The period of the greatest activity in this field of solid state chemistry and physics was from about 1970 to 1990. The intercalation reactions are defined as topotactic solid state reactions and the products – the intercalation compounds – clearly distinguished from inclusion and interstitial compounds. After a short historical introduction emphasizing the pioneering work of Ulrich Hofmann the central topics and concepts will be reviewed and commented. The most important ones in my view are: dichalcogenide intercalation compounds, the electrochemical intercalation and search for new battery electrodes, the physics of graphite intercalation compounds, the staging and interstratification phenomena. The relation to other fields of actual research and demands for forthcoming research will be also addressed. Introduction As far as I found the verb „to intercalate“ and the term „intercalation“ has been used for the first time by McDonnell et al. in 1951 without any explanation for using it. 1 In 1959 Rüdorff used the phrase „intercalation compounds“ in the title of a review about all chemical derivatives of graphite.2 In these compounds atoms or ions have been inserted (alternatively, intercalated, or in German „eingelagert") under expansion of the lattice perpendicular to the nearly unchanged graphite layers.
    [Show full text]
  • Stereo–Chemical Control of Organic Reactions in the Interlamellar Region of Cation–Exchanged Clay Minerals
    i Stereo–Chemical Control of Organic Reactions in the Interlamellar Region of Cation–Exchanged Clay Minerals By Vinod Vishwapathi A thesis submitted in partial fulfilment for the requirements for the degree of Doctor of Philosophy at the University of Central Lancashire March 2015 STUDENT DECLARATION FORM Concurrent registration for two or more academic awards Either *I declare that while registered as a candidate for the research degree, I have not been a registered candidate or enrolled student for another award of the University or other academic or professional institution ___________________________________________________________________________________ Material submitted for another award Either *I declare that no material contained in the thesis has been used in any other submission for an academic award and is solely my own work ___________________________________________________________________________________ (state award and awarding body and list the material below): * delete as appropriate Collaboration Where a candidate’s research programme is part of a collaborative project, the thesis must indicate in addition clearly the candidate’s individual contribution and the extent of the collaboration. Please state below: Signature of Candidate ______________________________________________________ Type of Award ___________PhD (Doctor of Philosophy)___________ School School of Forensics and Investigative Sciences______ iii Abstract Carbene intermediates can be generated by thermal, photochemical and transition metal catalysed processes
    [Show full text]
  • Nanoidentation Behavior of Clay Minerals and Clay-Based Nonstructured Multilayers" (2009)
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2009 Nanoidentation behavior of clay minerals and clay- based nonstructured multilayers Zhongxin Wei Louisiana State University and Agricultural and Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Civil and Environmental Engineering Commons Recommended Citation Wei, Zhongxin, "Nanoidentation behavior of clay minerals and clay-based nonstructured multilayers" (2009). LSU Doctoral Dissertations. 3033. https://digitalcommons.lsu.edu/gradschool_dissertations/3033 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. NANOINDENTATION BEHAVIOR OF CLAY MINERALS AND CLAY-BASED NANOSTRUCTURED MULTILAYERS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy In The Department of Civil and Environmental Engineering by Zhongxin Wei B.S., Tsinghua University, China, 1989 M.S., Tsinghua University, China, 1994 December, 2009 DEDICATION To my parents and my wife ii ACKNOWLEDGEMENTS I would like to express my sincere thanks to Dr. Guoping Zhang, my advisor, who provided me the opportunity and guided me to pursue my Ph.D degree in the academic area of geotechnical engineering. I have learned a lot from his outstanding knowledge and professional attitude, and I am grateful of his patient guidance and multiaspect supports which attribute to the accomplishment of this dissertation.
    [Show full text]
  • Environmental Chemistry
    Environmental Chemistry Keyword List — By Topic Chemistry & Chemicals— polysaccharides Chemistry & Chemicals— General proteins Pollutants (each element may act as a pyrethrins BTX [benzene, toluene, xylenes] keyword) radical ions carcinogens acids radicals CFCs [chlorofluorocarbons] agrochemicals RNA chlorinated organics alcohols solvation DDT, DDD, DDE alkaloids sulfides dioxins amino acids terpenes explosives analytical reagents trace elements fungicides anions transition metals genetically modified organisms bases ureas greenhouse gases carbohydrates urethanes herbicides carbon dioxide vinyl compounds metabolism-affecting agents cardiovascular agents vitamins mutation cations water nervous system agents chlorophylls xenobiotics nitroaromatics coal zeolites odouriferous compounds DNA PAHs [polycyclic aromatic drugs Chemistry & Chemicals—States hydrocarbons] enzymes of Matter parasiticides fatty acids aerosols PCBs [polychlorinated biphenyls] gastrointestinal agents aerosols (bio-) pesticides glycerides ceramics PCDDs [polychlorinated dibenzo- glycoproteins colloids para-dioxins] halogen compounds compost petroleum hormones crystals phenolics humic substances dusts polychlorinated dibenzofurans hydrocarbons electrolytes PCDFs [polychlorinated hydroxides emulsions dibenzofurans] ions explosives PTFE [polytetrafluoro ethylene] isocyanides fibres PVC [polyvinyl chloride] isotopes foods radiation lipopeptides gases radioactive elements lipoproteins gels toxicant metabolites glasses toxic elements metalloenzymes lipids metalloproteins liquids
    [Show full text]
  • CLAY MINERAL ORGANIC INTERACTIONS G. Lagalya, M
    Handbook of Clay Science Edited by F. Bergaya, B.K.G. Theng and G. Lagaly Developments in Clay Science, Vol. 1 309 r 2006 Elsevier Ltd. All rights reserved. Chapter 7.3 CLAY MINERAL ORGANIC INTERACTIONS G. LAGALYa, M. OGAWAb AND I. DE´ KA´ NYc aInstitut fu¨r Anorganische Chemie, Universita¨t Kiel, D-24118 Kiel, Germany bDepartment of Earth Sciences, Waseda University, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan cDepartment of Colloid Chemistry and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, H-6720 Szeged, Hungary Clay minerals can react with different types of organic compounds in particular ways (Fig. 7.3.1). Kaolin species (kaolinite, nacrite, and dickite) adsorb particular types of neutral organic compounds between the layers. The penetration of organic molecules into the interlayer space of clay minerals is called intercalation. Interca- lated guest molecules can be displaced by other suitable molecules. A broader diversity of reactions characterises the behaviour of 2:1 clay minerals. Water molecules in the interlayer space of smectites and vermiculites can be dis- placed by many polar organic molecules. Neutral organic ligands can form com- plexes with the interlayer cations. The interlayer cations can be exchanged by various types of organic cations. Alkylammonium ions, in industrial applications mainly quaternary alkylammonium ions, are widely used in modifying bentonites. The other important group of organic compounds are cationic dyes and cationic complexes. The interaction of clay minerals with different types of polymers including poly- peptides and proteins was intensely studied many decades ago and recently seems to revive.
    [Show full text]
  • Pierre D'hondt – Acting General Manager
    INTRODUCTION Pierre D'hondt – acting general manager A new mission SCK•CEN has been founded in 1952 to support the launching of nuclear scientific and industrial activities in Belgium. An important scientific research infrastructure and manpower is available to cover a comprehensive programme on the development of the nuclear fuel cycle. In 1991 our mission has been focused on the safety aspects of this cycle. Today our mission is: to perform research in priority to aspects related to safety, waste management, protection of men and environment, safeguarding of fuel and other strategic materials and to the social implications in an perspective of sustainable development; to develop, collect and disseminate the necessary knowledge through education and communication; to render services which are requested in our domain by the nuclear industry, the medical sector and the authorities to make the necessary multi-disciplinary scientific contacts related to the energy issues. Our infrastructure and skills To perform our mission, SCK•CEN is running large infrastructures: BR1 is the first Belgian research reactor started in 1956 and is still operational. This reactor is used for scientific research and education. BR2 is our materials testing reactor and plays an important role in research towards the behaviour of materials and fuel under irradiation. This research contributes to the safe exploitation of our Belgian and international reactors for electricity production. Hot-cells: SCK•CEN has, besides his research reactor, also an important hot-cell infrastructure to test the highly irradiated materials. BR3 was the first pressurized water reactor in Western-Europe. After 25 years of operation, this reactor was stopped in 1987 and is now under dismantling.
    [Show full text]
  • Exclusively from Astronomy Magazine
    INTRODUCINGINTRODUCING THETHE NEWNEW LX65LX65 SERIESSERIES At Meade, we believe the universe should be accessible to all and available at a moment’s notice. The new LX65 series telescope does this by combining advanced features and premium optics in an easy-to-use portable telescope system. This versatile GoTo telescope features our AudioStar® hand controller, all-metal worm-drive gearing, removable optical tube with Vixen-style dovetail, and secondary mounting saddle for attaching an additional OTA. The secondary saddle allows you to view objects both in wide field or close up and is ideal for astronomy outreach and is sure to impress anyone with its technology and optics. 6” Maksutov & 80mm APO* *(sold separately) Available with a 5" Maksutov 6" Maksutov 6" ACF or 8" ACF SINGLE-FORK ARM MOUNT - Sturdy single-arm design allows you to mount two optical tubes at once. The second saddle is fully adjustable allowing both tubes to be precisely pointed at the same object. PORTABLE BUILD - This portable scope breaks down into two compact pieces and does not require any tools. With its built-in carry handle, transporting the LX65 to your favorite dark-sky location is a breeze! 2nd Saddle with 7 lb. AUDIOSTAR® HAND BOX - Its 30,000-object database can take you on Payload! a guided tour of the night sky's best objects. With its built-in speaker, you can learn so much about the objects you're viewing! Focus Camera | focuscamera.com Agena | agenaastro.com Astronomics | astronomics.com Optics Planet | opticsplanet.com Adorama | adorama.com High Point Scientific | highpointscientific.com OPT Telescopes | optcorp.com B&H Photo Video | bhphotovideo.com Woodland Hill Camera | whcamera.com Online Content Code: ASY1808 Enter this code at: www.astronomy.com/code AUGUST 2018 to gain access to web-exclusive content VOL.
    [Show full text]
  • 2020 Tailings Research Report PUBLISHED AUGUST 2021
    COSIA TAILINGS EPA 2020 Tailings Research Report PUBLISHED AUGUST 2021 Introduction This is the third summary report from the Canada’s Oil Sands Innovation Alliance (COSIA) Tailings Environmental Priority Area (EPA). It highlights just some of the recent progress and research work in tailings management at various stages of research—from literature reviews, laboratory projects, pilot trials and to large, field-scale demonstration and commercialization programs. The COSIA Tailings EPA, in collaboration with universities, government and research institutes, other companies and partners, is bringing together shared experience, expertise and financial commitment of oil sands mining companies to find new technologies and solutions to tailings management. The COSIA Tailings EPA 2020 Tailings Research Report summarizes 40 active research projects, a few less than the first two summary reports. Several projects were completed, while others were put on hold. The COVID-19 pandemic presented unforeseen and unprecedented challenges for all involved in tailings research. COSIA member companies, universities, and other research collaborators faced challenges to advance the research projects as planned, while ensuring the health and safety of all involved and adhering to public health measures. Tailings are the sand, silt, clay, water and residual bitumen found naturally in oil sands that remain following the mining and bitumen extraction process. Through the COSIA Tailings EPA, member companies are focused on improving the management of oil sands tailings throughout their production and treatment, storage, reclamation and closure phases. The Tailings EPA has identified key issues facing the industry and is working to address them. The current areas of focus include: • minimizing the accumulation of fluid tailings (FT) within tailings ponds; • advancing treatment of process-affected water, the water which remains once the FT are removed; and • accelerating reclamation of tailings deposits so that they can be incorporated into the final closure landscape.
    [Show full text]
  • Structure and Properties of Nanoclay Reinforced Polymer Films, Fibers and Nonwovens
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 8-2009 Structure and Properties of Nanoclay Reinforced Polymer Films, Fibers and Nonwovens Raghavendra Ratnakar Hegde University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Polymer and Organic Materials Commons Recommended Citation Hegde, Raghavendra Ratnakar, "Structure and Properties of Nanoclay Reinforced Polymer Films, Fibers and Nonwovens. " PhD diss., University of Tennessee, 2009. https://trace.tennessee.edu/utk_graddiss/39 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Raghavendra Ratnakar Hegde entitled "Structure and Properties of Nanoclay Reinforced Polymer Films, Fibers and Nonwovens." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Polymer Engineering. Gajanan Bhat,, Major Professor We have read this dissertation and recommend its acceptance: Roberto Benson, Joseph Spruiell, David Joy Accepted
    [Show full text]
  • TZENG-DISSERTATION-2015.Pdf
    GAS BARRIER AND SEPARATION BEHAVIOR OF LAYER-BY-LAYER ASSEMBLIES A Dissertation by PING TZENG Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Chair of Committee, Jaime C. Grunlan Committee Members, David Bergbreiter Jodie Lutkenhaus Victor Ugaz Head of Department, M. Nazmul Karim May 2015 Major Subject: Chemical Engineering Copyright 2015 Ping Tzeng ABSTRACT Thin films with the ability to control gas permeability are crucial to packaging and purification applications. The addition of impermeable nanoparticles into neat polymers improves barrier/separation properties by creating a tortuous pathway, but particle aggregation occurring at high filler loading can reduce transparency of these composites as well as barrier/separation improvement. Layer-by-layer (LbL) assembly allows full control of morphology at the nanoscale, so barrier/separation properties can be precisely controlled and the films remain flexible and transparent. A three component recipe, consisting of polyvinylamine, poly(acrylic acid) and montmorillonite clay was deposited as repeating PVAm/PAA/PVAm/MMT quadlayers (QL) via LbL assembly. By adjusting solution pH and varying the placement of polycation layers, polymer interdiffusion and clay concentration were controlled, as well as oxygen barrier. Another QL assembly, with a PEI/PAA/PEI/MMT repeating sequence, was deposited using LbL to create light gas barrier films. Transmission electron microscope images revealed a highly-oriented nanobrick wall structure. A 5 QL coating on 51 µm polystyrene (PS) is shown to lower both hydrogen and helium permeability three orders of magnitude relative to bare PS, demonstrating better performance than ethylene vinyl- alcohol (EVOH) copolymer film and even metallized plastic.
    [Show full text]