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Effect of Structure and Plasticizer on the Glass Transition of Adsorbed Polymer

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Effect of Structure and Plasticizer on the Glass Transition of Adsorbed Polymer Scholars' Mine Doctoral Dissertations Student Theses and Dissertations Fall 2010 Effect of structure and plasticizer on the glass transition of adsorbed polymer Boonta Hetayothin Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Chemistry Commons Department: Chemistry Recommended Citation Hetayothin, Boonta, "Effect of structure and plasticizer on the glass transition of adsorbed polymer" (2010). Doctoral Dissertations. 1901. https://scholarsmine.mst.edu/doctoral_dissertations/1901 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. EFFECT OF STRUCTURE AND PLASTICIZER ON THE GLASS TRANSITION OF ADSORBED POLYMER by BOONTA HETAYOTHIN A DISSERTATION Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in CHEMISTRY 2010 Approved by Frank D. Blum, Advisor Michael Van De Mark Jay A. Switzer Prakash Reddy Douglas Ludlow 2010 Boonta Hetayothin All Rights Reserved iii PUBLICATION DISSERTATION OPTION The papers included in this dissertation have been prepared in the style of the journal, Macromolecules. Paper I (pages 29-47), Paper II (pages 48-64), Paper III (pages 65-88) and Paper IV (pages 89-111). The Paper V (pages 112-119) has been published by Polymer Preprints and added as the supporting document for Paper I and II. Appendices have been added to include additional characterization and simulation information. iv ABSTRACT The effect of molecular mass on adsorbed poly(methyl methacrylate) (PMMA) on silica was determined using temperature-modulated differential scanning calorimetry (TMDSC). A two-component model, based on loosely-bound polymer (glass transition temperature, Tg, similar to that of bulk) and tightly-bound polymer (Tg higher than that of bulk) was used to interpret the thermograms. Similar amounts of tightly-bound polymer were found for 450 and 85 kDa PMMA (0.78 mg/m2), while the 32 kDa sample had a smaller amount (0.48mg/m2). A comparison of adsorbed PMMA, poly(vinyl acetate) (PVAc), and poly(methyl acrylate) (PMA) on silica was made using the same technique. The amounts of tightly-bound PMMA (0.78 mg/m2), PVAc (0.78 mg/m2), and PMA (0.72 mg/m2), adsorbed on silica surfaces did not differ much. The ratios of heat capacity increments of the loosely- and tightly-bound components (ΔCpA/ΔCpB) at Tg, indicating the relative mobility of the two components, were also estimated to be about 1.8. The dynamics of the phenyl-deuterated plasticizer di(propylene glycol) dibenzoate in bulk and adsorbed PVAc on silica were probed using solid-state 2H NMR. The dynamics of this plasticizer in the plasticized-bulk polymer system were found to be heterogeneous. For adsorbed PVAc on silica, the dynamics of the plasticizer was found to be even more motionally heterogeneous than that observed in bulk samples. The NMR results provided solid evidence that, when there is only a small amount of adsorbed polymer (i.e., 0.8 mg/m2), the plasticizer has very little or almost no effect on the dynamics of that polymer. The plasticizer was observed to be effective at higher adsorbed amounts. v ACKNOWLEDGMENTS I would like to thank Dr. Frank D. Blum for all of his patience, forgiveness, and advising during my graduate career at Missouri S&T. I thank my committee members, Dr. Michael Van De Mark and Dr. Prakash Reddy for being encouraging and advising me, and Dr. Jay A. Switzer and Dr. Douglas Ludlow for their thoughtful comments and suggestions. I thank the both present and past members of the Blum research group, Dr. Manikantan Nair, Dr. Piyawan Krisanangkura, Dr. Zhefei Li, Krunal Waghela, Xiaoming Cheng, Tan Zhang, Jong-Sik Moon and summer students Mark Hickle and Adam Daily. I also thank Dr. Robert O’ Connor for his useful discussion on NMR project. I thank Ms. Barbara Harris for all of her assistance with editing. I also thank Raymond Kendrick and Joe Council for technical support with NMR and TMDSC projects. I thank my great collaborator Roy Cabaniss from the Computer Science Department for his assistance with the NMR simulation program. I thank Dr. Cyriac Kandoth and Waraporn Viyanon for their help on Fortran programming. I also thank Dr. Tadashi Tokuhiro, Dr. Terry Bone, Dr. Pericles Stavropoulos, Dr. Woelk Klaus, Dr. Jeff Winiarz and staff members of Chemistry Department; Dean Lenz, Mike Myers, Dave Satterfield, Kathy Eudaly, Donna Riggs, Carol Rodman and Dr. Eric Bohannan at Materials Research Center. I thank Jeanine Bruening at the Writing Center and Dr. Neil Book at Chemical & Biological Engineering Department. I acknowledge the Chemistry Department, the Materials Research Center of Missouri University of Science and Technology and the National Science Foundation (NSF) for financial support of this research. I also acknowledge the ACS South Central Missouri Local Section for the travel grant to the ACS national meeting. Finally, I thank my husband Floyd, my parents and siblings in Thailand, my parents in law Elaine & Floyd, my friends Rolla and Sierra for being tremendous supportive throughout my graduate career and to make this work is possible. vi TABLE OF CONTENTS Page PUBLICATION DISSERTATION OPTION.................................................................... iii ABSTRACT ....................................................................................................................... iv ACKNOWLEDGMENTS .................................................................................................. v LIST OF ILLUSTRATIONS .............................................................................................. x LIST OF TABLES ........................................................................................................... xiv NOMENCLATURE ......................................................................................................... xv SECTION 1. INTRODUCTION ................................................................................................. 1 REFERENCES ...................................................................................................... 3 2. BACKGROUND ................................................................................................... 4 2.1. ADSORPTION ............................................................................................... 4 2.1.1. Polymer Conformations in Solution. .................................................... 4 2.1.2. Thermodynamics of Polymer Solution................................................. 5 2.1.3. Surface Tension of Polymer Solutions, ............................................ 7 2.1.4. Polymers at Interfaces. ......................................................................... 8 2.1.5. Important Features of Interfacial Polymers (Adsorbed Amounts and Interfacial Structures). ................................ 10 2.2. GLASS TRANSITION TEMPERATURE, Tg ............................................. 10 2.2.1. Free Volume Theories on Tg. .............................................................. 11 2.2.2. Factors That Affect The Tg. ................................................................ 11 2.3. CHARACTERIZATION TECHNIQUES FOR POLYMERIC MATERIALS ................................................................................................ 14 2.3.1. Differential Scanning Calorimetry (DSC) .......................................... 16 2.3.2. Temperature Modulated Differential Scanning Calorimetry (TMDSC) ....................................................................... 18 2.3.3. Solid State Deuterium (2H) NMR ...................................................... 20 2.4. REFERENCES ............................................................................................. 26 vii PAPER 1. THERMAL ANALYSIS OF ADSORBED POLY(METHYL METHACRYLATE) ON SILICA: EFFECT OF MOLECULAR MASS .............. 29 ABSTRACT ......................................................................................................... 29 1. INTRODUCTION ........................................................................................... 30 2. EXPERIMENTAL ........................................................................................... 32 2.1. Model........................................................................................................ 34 3. RESULTS ........................................................................................................ 35 4. DISCUSSION .................................................................................................. 39 5. CONCLUSIONS.............................................................................................. 44 6. ACKNOWLEDGEMENTS ............................................................................. 45 7. REFERENCES ................................................................................................ 45 2. COMPARISON OF HYDROGEN-BONDED POLYMERS ON SILICA USING TEMPERATURE-MODULATED DIFFERENTIAL SCANNING CALORIMETRY..................................................................................................... 48 ABSTRACT ......................................................................................................... 48 1. INTRODUCTION
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