DEFORMATION STUDIES OF POLYMERS AND POLYMER/CLAY NANOCOMPOSITES A Dissertation Presented to The Academic Faculty by Bilge Gurun In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Polymer, Textile and Fiber Engineering Georgia Institute of Technology December 2010 COPYRIGHT 2010 BY BILGE GURUN DEFORMATION STUDIES OF POLYMERS AND POLYMER/CLAY NANOCOMPOSITES Approved by: Dr. David G. Bucknall, Co-advisor Dr. Donggang Yao School of Polymer, Textile and Fiber School of Polymer, Textile and Fiber Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Yonathan S. Thio, Co-advisor Dr. Kenneth Gall School of Polymer, Textile and Fiber School of Materials Science and Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Haskell W. Beckham School of Polymer, Textile and Fiber Engineering Georgia Institute of Technology Date Approved: October 22, 2010 To the everlasting love and support of my Dad, my Mom, my Sister and my Husband… ACKNOWLEDGEMENTS First and foremost, I would like to express my gratitude to my advisors, David Bucknall and Yonathan Thio who gave me an opportunity to work with them as their student at GaTech. They supervised me with their knowledge and experience throughout my time at GaTech, especially when things were tough. It was a great experience to work with them. I would like to thank - Drs. Beckham, Yao and Gall for serving on my dissertation committee and for their most valued inputs. I would like to thank all of them once more for allowing me to use their lab space and equipment whenever I needed. I am grateful to - Drs. Kumar and Minus for training me and letting me use their X-ray facility. I am also thankful to Dr. Jacob for his support and understanding throughout my time at PTFE. There is a number my colleagues who have helped me during this time. I would like to thank Ram, Yong Ho, Sehoon, Sarang and Mihir for their helpful discussions on classes and qualifier as well as different aspects of my project. I would like to thank the administrative staff – Dan, Mike, Angie, Hope and Linda for helping me take care of other things so I could do my research more effectively. Many thanks to my former and current group members Katie, Hannah, Xi and Deepali for making life easier and more bearable for me. I especially want to thank Katie and Rebecca for staying up all night with me during the synchrotron experiments and working as if it is their own. I appreciate their hard work, stamina and support. I have to thank many other friends, whom I do not have enough space here to list their names, for their unconditional and supporting friendship. iv I would like to thank my dad, mom and sister for their constant encouragement through phone calls. I would like to thank them for believing in me and trusting all my decisions. Last but not least, I would like to thank my beloved husband, Gokce Gurun. He is my love and my life. I feel special for having him in my life and I am grateful to him for being on my side and supporting me all the time. Without him believing in me, I could not have come to finish this work. v TABLE OF CONTENTS ACKNOWLEDGEMENTS ........................................................................................... iv LIST OF TABLES ........................................................................................................ ix LIST OF FIGURES .........................................................................................................x SUMMARY .................................................................................................................xvi LIST OF SYMBOLS AND ABBREVIATIONS...........................................................xix CHAPTER I INTRODUCTION ......................................................................................1 1.1 Motivation .............................................................................................................1 1.2 Scope of Dissertation .............................................................................................3 CHAPTER II LITERATURE REVIEW ..........................................................................4 2.1 Polymer composites in general ...............................................................................4 2.2 Polymer nanocomposites in general .......................................................................6 2.3 Structure and Properties of Layered Silicates ....................................................... 11 2.4 Polymer – Layered Silicate (PLS) Nanocomposites .............................................. 14 2.4.1 Preparation of PLS nanocomposites .............................................................. 17 2.4.2 Existing and potential applications for PLS nanocomposites.......................... 20 2.4.3 Characterization Techniques for PLS Nanocomposites .................................. 22 2.5 X-ray scattering from polymers ............................................................................ 25 2.6 Synchrotron radiation – Brief history and basics .................................................. 31 2.6.1 Synchrotron X-rays in Polymer Science ........................................................ 35 CHAPTER III DESIGN OF IN-SITU MULTI-AXIAL DEFORMATION DEVICE (IMDD) ......................................................................................................................... 46 3.1 Discussions on earlier biaxial and multiaxial deformation designs ........................ 47 vi 3.2 Design of In-situ Multiaxial Deformation Device (IMDD) ................................... 52 3.2.1 Design of heating unit for higher temperature studies .................................... 60 3.3 Design of the In-situ Biaxial Deformation Device (IBDD) ................................... 61 CHAPTER IV MATERIALS, METHODS AND TECHNIQUES.................................. 66 4.1 Materials and Sample Preparation ........................................................................ 66 4.2 Thermal Analysis ................................................................................................. 67 4.3 Melt Rheology Experiments ................................................................................. 68 4.4 Laboratory Based X-ray Measurements................................................................ 68 4.5 In-situ X-Ray Studies ........................................................................................... 69 4.6 Ex-situ Biaxial and Tensile Mechanical Measurements ........................................ 74 CHAPTER V RESULTS AND DISCUSSIONS ON PE AND PE/CLAY NANOCOMPOSITES ................................................................................................... 77 5.1 Mechanical Properties .......................................................................................... 77 5.2 Thermal Properties ............................................................................................... 80 5.3 General in-situ X-ray Observations ...................................................................... 82 5.3.1 Influence of Temperature .............................................................................. 94 5.3.2 Influence of Strain Rate ............................................................................... 105 5.4 Time dependent recovery after multiaxial deformation ....................................... 109 CHAPTER VI RESULTS AND DISCUSSIONS ON PP AND PP/CLAY NANOCOMPOSITES ................................................................................................. 116 6.1 Mechanical Properties ........................................................................................ 116 6.2 Thermal Properties ............................................................................................. 120 6.3 General In-situ X-ray Observations .................................................................... 121 6.3.1 Influence of temperature.............................................................................. 129 vii 6.3.2 Influence of strain rate ................................................................................. 136 6.4 Effect of shear deformation ................................................................................ 142 6.5 Time dependent recovery after multiaxial deformation ....................................... 150 CHAPTER VII CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE WORK .................................................................................................................................... 154 7.1 Conclusions ....................................................................................................... 154 7.2 Recommendations for future work ..................................................................... 158 APPENDIX A MULTIAXIAL DEFORMATION DATA OF PE AND PP NANOCOMPOSITE SYSTEMS ................................................................................. 161 APPENDIX B EX-SITU UNIAXIAL DEFORMATION BEHAVIOR OF PE AND PENCS ........................................................................................................................ 163 APPENDIX C SHEAR DEFORMATION AND WAXS STUDIES ON SHEARED PP AND PPNC SAMPLES ............................................................................................... 168 APPENDIX D PEAK FITTING ANALYSIS ON WAXS DATA ................................ 172 REFERENCES ...........................................................................................................