BIO-BASED FLAME RETARDATION OF ACRYLONITRILE-BUTADIENE-STYRENE by GUSTAVO SCHINAZI Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Macromolecular Science and Engineering CASE WESTERN RESERVE UNIVERSITY January, 2021 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the dissertation of Gustavo Schinazi candidate for the degree of Doctor of Philosophy*. Committee Chair and Advisor David A. Schiraldi Committee Member and Co-Advisor Jonathan K. Pokorski Committee Member and Co-Advisor José Roberto Moraes d’Almeida Committee Member Gary E. Wnek Committee Member Hatsuo Ishida Committee Member Ya-Ting T. Liao Committee Member Mônica Feijó Naccache Committee Member Amanda Lemette Teixeira Brandão Date of Defense October 21, 2020 *We also certify that written approval has been obtained for any proprietary material contained therein. Dedicado à Vovó Geny pelo seu amor incondicional e infinito. Meu amor por você é maior do que o mundo inteiro. Dedicated to my Grandma, Vovó Geny, for your unconditional and infinite love. My love for you is bigger than the entire world. iv Table of Contents 1. INTRODUCTION AND LITERATURE REVIEW ...............................................2 1.1. Introduction, Objectives, and Methodology ....................................................... 2 1.2. Literature Review ................................................................................................. 6 1.2.1. The Combustion Cycle and Ways to Suppress It ................................................. 6 1.2.2. Flame Retardants – Definition, Modes of Action, and Classification ................ 10 1.2.2.1. Physical Modes of Action ................................................................................. 11 1.2.2.2. Chemical Modes of Action ............................................................................... 12 1.2.2.3. Condensed Phase vs. Gas Phase ...................................................................... 13 1.2.3. Commercial Flame Retardants ........................................................................... 14 1.2.3.1. Halogenated Flame Retardants ....................................................................... 15 1.2.3.1.1. General Information ....................................................................................... 15 1.2.3.1.2. Main Issues .................................................................................................... 17 1.2.3.2. Organophosphorus Flame Retardants ............................................................. 20 1.2.3.2.1. General Information ....................................................................................... 20 1.2.3.2.2. Main Issues .................................................................................................... 21 1.2.3.3. Inorganic Flame Retardants ............................................................................ 21 1.2.3.3.1. General Information ....................................................................................... 21 1.2.3.3.2. Main Issues .................................................................................................... 23 1.2.3.4. Nitrogen-Based Flame Retardants ................................................................... 24 1.2.3.4.1. General Information ....................................................................................... 24 1.2.3.4.2. Main Issues .................................................................................................... 25 1.2.4. Bio-Sourced Flame Retardants ........................................................................... 26 1.2.5. Acrylonitrile-Butadiene-Styrene (ABS) ............................................................. 41 v 2. EXPERIMENTAL....................................................................................................47 2.1. Materials .............................................................................................................. 47 2.2. Methodology ........................................................................................................ 49 2.3. Sample Preparation ............................................................................................ 51 2.3.1. Drying of Starting Materials ............................................................................... 51 2.3.2. Melt Processing for Phase 1 (Screening Phase) ................................................. 52 2.3.2.1. Batch Mixing .................................................................................................... 52 2.3.2.2. Phase 1 Compression Molding ........................................................................ 53 2.3.2.3. Sample Cutting for Vertical Burn Testing ........................................................ 53 2.3.3. Melt Processing for Phase 2 (Detailed Analysis and Mechanistic Study Phase) 54 2.3.3.1. Extrusion .......................................................................................................... 54 2.3.3.2. Phase 2 Compression Molding ........................................................................ 55 2.3.3.3. Injection Molding ............................................................................................. 56 2.4. Characterization ................................................................................................. 56 2.4.1. Vertical Burn Testing ......................................................................................... 56 2.4.2. Microscale Combustion Calorimetry ................................................................. 57 2.4.3. Cone Calorimetry ............................................................................................... 58 2.4.4. Thermogravimetric Analysis .............................................................................. 59 2.4.5. Pyrolysis-Gas Chromatography-Mass Spectrometry ......................................... 60 2.4.6. Tensile Testing ................................................................................................... 63 2.4.7. Impact Testing .................................................................................................... 64 3. BIO-BASED FLAME RETARDATION OF ABS EVALUATED BY MICROSCALE COMBUSTION CALORIMETRY ...................................................67 3.1. Introduction ......................................................................................................... 67 3.2. Experimental Planning and Design of Experiments ........................................ 73 vi 3.2.1. Material Selection ............................................................................................... 73 3.2.2. Selection of Fabrication and Analysis Techniques ............................................ 80 3.2.3. Preliminary Experiments .................................................................................... 82 3.2.3.1. Determination of Melt-Processing Parameters ............................................... 82 3.2.3.2. Evaluation of Processing Effect on Material Properties ................................. 84 3.2.3.3. Selection of Type and Amount of Compatibilizer ............................................. 88 3.2.3.3.1. Vertical Burn Testing for Compatibilizer Evaluation ................................... 90 3.2.3.3.2. Microscale Combustion Calorimetry for Compatibilizer Evaluation ............ 92 3.2.4. Design of Experiments for Determination of Sample Compositions ................. 94 3.2.4.1. First Set of Samples .......................................................................................... 95 3.2.4.2. Second Set of Samples ...................................................................................... 99 3.3. Flammability Results and Discussion.............................................................. 102 3.3.1. Vertical Burn Testing ....................................................................................... 102 3.3.2. Microscale Combustion Calorimetry ............................................................... 114 3.3.2.1. MCC Curves and Results ............................................................................... 114 3.3.2.2. Additive Hypothesis and the Quantification of Synergy ................................ 125 3.3.2.3. Synergistic Analysis Based on MCC Results ................................................. 134 3.4. Conclusions ........................................................................................................ 141 4. DETAILED ANALYSIS AND MECHANISTIC STUDY OF BIO-BASED FLAME-RETARDANT ABS COMPOSITES ............................................................145 4.1. Introduction ....................................................................................................... 145 4.2. Cone Calorimetry.............................................................................................. 148 4.2.1. Direct Cone-Calorimetry Results ..................................................................... 149 4.2.2. Results and Mechanisms from MCC-Cone Calorimetry Comparisons ........... 159 4.3. Microscale Combustion Calorimetry and Thermogravimetric Analysis .... 172 vii 4.3.1. Revisiting Microscale Combustion Calorimetry .............................................. 172 4.3.2. Thermogravimetric Analysis ............................................................................ 180 4.3.3. MCC-TGA Comparison and Activation Energy .............................................