ANALYZING and IMPROVING VISCOELASTIC PROPERTIES of HIGH DENSITY POLYETHYLENE by REAJ UDDIN AHMED Bachelor of Science in Mechanic
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ANALYZING AND IMPROVING VISCOELASTIC PROPERTIES OF HIGH DENSITY POLYETHYLENE By REAJ UDDIN AHMED Bachelor of Science in Mechanical Engineering Bangladesh University of Engineering and Technology Dhaka, Bangladesh 2009 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE July, 2011 ANALYZING AND IMPROVING VISCOELASTIC PROPERTIES OF HIGH DENSITY POLYETHYLENE Thesis Approved: Dr. Jay C. Hanan Thesis Adviser Dr. Ranji Vaidyanathan Dr. Sandip Harimkar Dr. Mark E. Payton Dean of the Graduate College . ii ACKNOWLEDGMENTS First of all, I would like to show my heartiest gratitude to my supervisor, Dr. Jay C. Hanan, who has been very helpful throughout my entire Masters Program. His guidance, inspiration and support from the beginning of my graduate studies gave me constant motivation to perform this work. I consider myself lucky to be able to work under his supervision. I would also like to thank Dr. Ranji Vaidyanathan, for his immense help in this thesis. I worked in his lab for a major part of this work and his mentoring and constructive suggestions really mean a lot to me. I would also like to thank Dr. Sandip Harimkar for agreeing to be a member in my thesis committee. I am also thankful to Niagra Bottling LLC, for funding the project. I would like to thank Dr. Tzuchia Erica Tseng and Mr. Bill Hall for helping me with the samples. I would also like to thank Dr. Liz Orwin for helping regarding equipments. Special thanks go to Sudheer Bandla, who has always been very helpful and taught me many things. I would like to thank my colleagues Mazhar Islam, Ranjan Ganapthi Mahadevan, Massod Allakarami, Advait Bhat, Balaji Jayakumar, Rohit Vaidya, Praful Bari for their assistance in my work. My friends Krishnan Lakshminarayanan, Seshasai , Gandikota, Mrinalini Mulukutla, Sarat Das, Nazmul Khan Shahan, Mehedi Sarwar also helped me in many ways while I was working for this thesis. Last, but not least, I would like to show my gratitude to my parents, brother and sister for their patience and understanding during my studies in abroad. iii TABLE OF CONTENTS TABLE OF CONTENTS ................................................................................................... iv LIST OF TABLES ............................................................................................................ vii LIST OF FIGURES ......................................................................................................... viii CHAPTER I ...................................................................................................................... 1 1. INTRODUCTION ....................................................................................................... 1 1.1. Polyethylene (PE) ................................................................................................. 1 1.1.1. Types of PE ................................................................................................... 3 1.2. High Density Polyethylene (HDPE) .................................................................... 4 1.3. Viscoelasticity, Creep, and Stress Relaxation of Polymers ................................. 6 1.3.1. Simple Model for Creep and Stress Relaxation ............................................ 9 CHAPTER II ................................................................................................................... 15 2. OPTIMIZATION OF HDPE PROPERTIES ............................................................ 15 2.1. Motivation .......................................................................................................... 15 2.2. Viscoelasticity of HDPE .................................................................................... 16 2.3. Approaches ......................................................................................................... 18 2.3.1. Additives: CaCO 3........................................................................................ 18 2.3.2 Ageing and Annealing ................................................................................ 23 2.3.2.1. Ageing in Amorphous Material ........................................................... 24 2.3.2.2. Ageing in Semi-Crystalline Materials ................................................. 25 2.3.2.3. Residual Stresses and Ageing .............................................................. 26 2.3.2.4. Annealing............................................................................................. 27 CHAPTER III ................................................................................................................. 29 3. MATERIALS AND METHOD................................................................................. 29 3.1. Dynamic Mechanical Analysis (DMA).............................................................. 29 3.1.1. Introduction and Working Principle ........................................................... 29 3.1.2. ASTM recommendation for Dynamic Mechanical Analysis...................... 31 iv 3.1.3 DMA Q800 ................................................................................................. 32 3.1.3.1. Clamps of DMA Q800 ........................................................................ 34 3.1.3.1.1. Tension Film Clamp ......................................................................... 35 3.1.3.2. Calibration of DMA Q800 .................................................................. 36 3.1.3.2.1. Electronics Calibration .................................................................... 36 3.1.3.2.2. Force Calibration (Balance and Weight) ......................................... 37 3.1.3.2.3. Dynamic Calibration ......................................................................... 37 3.1.3.2.4. Position Calibration .......................................................................... 38 3.1.3.2.5. Clamp Calibration ............................................................................. 38 3.1.4. Sample used for DMA Q800 ...................................................................... 38 3.1.4.1. HDPE-CaCO 3 Composites .................................................................. 38 3.1.4.2. Neat HDPE from Closure .................................................................... 40 3.1.5. Tests and Parameters................................................................................... 42 3.1.5.1. HDPE-CaCO 3 Composites .................................................................. 42 Stress Strain ........................................................................................................ 42 Viscoelasticity .................................................................................................... 43 Creep Tests ......................................................................................................... 44 Stress Relaxation Test ........................................................................................ 46 3.1.5.2. Neat HDPE from Closure .................................................................... 46 3.2. Density of HDPE-CaCO 3 composites ................................................................ 47 3.3. Seal Failure from Squeeze Pressure ................................................................... 48 3.3.1. Methods....................................................................................................... 49 CHAPTER IV .................................................................................................................. 51 4. RESULTS AND DISCUSSION ................................................................................ 51 4.1. HDPE-CaCO 3 Composites ................................................................................. 51 4.1.1. Stress Strain curves for HDPE-CaCO 3 ....................................................... 51 4.1.2. Viscoelastic properties ................................................................................ 52 4.1.2.1. As a Function of Temperature ............................................................. 52 4.1.2.2. As a Function of Frequency ................................................................. 56 4.1.3. Creep Behavior ........................................................................................... 59 4.1.3.1 Short Term Creep .................................................................................... 59 v 4.1.3.2 Long Term Creep .................................................................................... 61 4.1.4. Stress Relaxation ......................................................................................... 64 4.2. Neat HDPE from Closure ................................................................................... 68 4.2.1 Ageing ......................................................................................................... 68 4.2.1.1 Non-annealed samples............................................................................. 68 4.2.1.2 Annealed samples .................................................................................... 72 Annealed for 30 minutes .................................................................................... 72 Annealed for 1 hour............................................................................................ 74 4.2.2. Annealing .................................................................................................... 77 4.3. Seal