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Flame Retardants for ABS and ABS-Matrix Wood-Plastic Composites

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Flame Retardants for ABS and ABS-Matrix Wood-Plastic Composites Graduate Theses, Dissertations, and Problem Reports 2008 Flame Retardants for ABS and ABS-matrix Wood-Plastic Composites Tze-Wei Liu West Virginia University Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Liu, Tze-Wei, "Flame Retardants for ABS and ABS-matrix Wood-Plastic Composites" (2008). Graduate Theses, Dissertations, and Problem Reports. 4397. https://researchrepository.wvu.edu/etd/4397 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Flame Retardants for ABS and ABS-matrix Wood-Plastic Composites Tze-Wei Liu Dissertation submitted to the College of Engineering and Mineral Resources At West Virginia University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Engineering Rakesh K. Gupta, Ph.D. Eung H. Cho, Ph.D. Caulton Irwin, Ph.D. Edwin L. Kugler, Ph.D. John Zondlo, Ph.D. Department of Chemical Engineering West Virginia University Morgantown, West Virginia 2008 Keywords: flame retardants, non-halogenated flame retardants, polymer recycling, acrylonitrile-butadiene-styrene, wood plastic composites, char formation, FTIR, flammability, thermal degradation. Copyright 2008 Tze-Wei Liu Abstract Flame Retardants for ABS and ABS-matrix Wood-Plastic Composites Tze-Wei Liu The goal of this study was to recycle acrylonitrile-butadiene-styrene (ABS) into wood plastic composites (WPCs). One major concern in this application is flammability. Thus, halogenated and non-halogenated flame retardants (FRs) were investigated. FRs were mixed with ABS using an internal mixer or an extruder, and samples were molded using a hot press or an injection molding machine. Mechanical properties were assessed by flexural tests, and flammability was measured by UL-94 type tests and limiting oxygen index. Thermogravimetric analysis (TGA) and FTIR were also performed in order to understand the decomposition behavior of ABS-based WPCs. Mechanical results showed that adding wood flour and FRs to ABS increased its flexural modulus; however, the addition of FRs into ABS-based WPCs reduced the flexural strength. All FRs could help to reach V-0 rating on the UL-94 test, but use of ammonium polyphosphate (AP423) required the least amount (20wt%) of FR when the wood content was fixed at 30wt%. Also, synergism existed between halogenated and non-halogenated FRs. From TGA curves, the shift of the first peak of Rmax (maximum weight change rate) of ABS-based WPCs to a lower temperature with addition of non-halogenated FRs indicated that a dehydration reaction took place between wood and FRs. This was further verified by FTIR study. Common fillers, such as talc or calcium carbonate, likely to be present in recycled ABS were found to negatively affect the fire retardancy of ABS-based WPCs. However, one could add a coupling agent to recover the fire performance. It was found that the coupling agent, after decomposition, formed a cross-linked network with non-halogenated FRs. Polybutadiene (PB) could further improve the fire resistance of ABS-based WPCs; however, high loading levels led to a poor dispersion, resulting in negative effects. Further, the use of triphenyl phosphate (TPP) shows synergism with AP423 in fire retardancy, and it also enhances the color of ABS-based WPCs. Another way to get improved color is to use gentler extrusion processing. By comparing ABS-based WPCs to polyolefin-based WPCs at the same level of fire performance, it was found that ABS-based WPCs had better performance in mechanical properties, indicating that ABS-based WPCs could have wider applications than ever polyolefin-based WPCs. By minimizing the amount of added wood, one can flame retard ABS. Here, a halogen-free flame retardant system was developed for ABS using cellulose as a charring material and APP as a catalyst. The use of these additives permits compounding and injection molding of ABS at low temperatures. The resulting materials have an attractive balance of mechanical properties and can achieve a V-0 or V-1 rating on UL-94 type tests. Acknowledgements I would like to thank Dr. Rakesh K. Gupta for his guidance in the development of the dissertation. I am so thankful I was able to work with such a great advisor. I would like to thank Dr. Satish K. Gaggar for his advice and assistance during the months that he was visiting here. This guidance really helped this project be the best it could be. I would like to thank Dr. Sushant Agarwal for his assistance and support. I really appreciate all your help. I would like to thank Dr. Adam Al-Mulla for his assistance and suggestions during his sabbatical leave at West Virginia University. I would like to thank Dr. Dady Dadyburjor and the Chemical Engineering Department for their help in giving me an excellent education. I would like to thank Jim Hall for all his technical help and assistance. I would like to express my gratitude to Linda Rogers and Bonita Helmick for their great secretarial work. I would like to thank the U.S. Department of Energy for funding this research project. To my family- Without you; I would have never been able to get through the past years. Knowing that I always had your love and support, I was able to make it through the tough parts of the previous years. Last, but not least, I would like to thank my wife and best friend, Yin-Han, for being there for me and giving me inspiration on a daily basis. iii Table of contents Abstract............................................................................................................................................ ii Acknowledgements......................................................................................................................... iii Table of contents............................................................................................................................. iv List of Figures............................................................................................................................... viii List of Tables................................................................................................................................. xvi List of Symbols........................................................................................................................... xviii Chapter 1 Introduction ..................................................................................................................... 1 1.1 Polymers- advantages and disadvantages .................................................................................. 1 1.2 Wood Plastic Composites........................................................................................................... 5 1.3 Objectives .................................................................................................................................. 9 1. Investigation of thermal and mechanical properties and flammability behavior of ABS/wood flour composites........................................................................................................................... 9 2. Examine the effect of fillers on the flammability of ABS based WPCs ................................ 10 3. Investigation of mechanical and thermal properties and flammability of recycled ABS/wood composites.................................................................................................................................. 10 4. The role of rubber on the effect of fire retardancy of ABS/wood composites....................... 10 5. Investigate the possibility of using non-halogenated flame retardants for virgin ABS ......... 10 Chapter 2 Literature Review.......................................................................................................... 12 2.1Acrylonitrile-butadiene-styrene (ABS) copolymer................................................................... 12 2.2 Thermal degradation or decomposition of polymers ............................................................... 17 2.3 Halogen-containing flame retardants....................................................................................... 20 2.4 Phosphorus-containing flame retardants.................................................................................. 24 2.5 Intumescent flame retardant systems....................................................................................... 27 2.6 Char formation......................................................................................................................... 33 2.7 Inorganic hydroxides as flame retardants ................................................................................ 36 2.8 Polymer nanocomposites ......................................................................................................... 38 2.9 Reinforced Thermoplastics .....................................................................................................
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