ABSTRACT KOLELL, HANNAH JOY. Hydrophobic Disperse and Polymeric Dyes for the Coloration of UHMWPE Medical Sutures. (Under the direction of Dr. Harold S. Freeman). Ultra-high molecular weight polyethylene (UHMWPE) has extremely beneficial properties, including being high strength at a relatively low weight. However, its high crystallinity and very hydrophobic nature make coloration from a dyebath difficult. Attempts at surface modification of the polymer to increase dyeability often adversely affect the desired high-performance properties. UHMWPE has applications in the medical field, including as sutures, and for surgical purposes coloration at sufficient visibility levels is of high importance. Currently, there is one FDA certified dye, D&C Violet 2, that has the ability to dye UHMWPE sutures. Thus, having additional dyes is of interest as long as the resulting color is not red. To achieve this goal, the present study pertained to the modification of various FDA certified dyes to make them suitable for dyeing PE sutures. Specifically, dyes such as C.I. Solvent Yellow 18 and C.I. Solvent Green 3 (D&C Green 6) were modified with C-4 to C-6 alkyl groups and after structure confirmation through HPLC, UV-Vis, NMR, and HR-MS, the resulting 6 dyes were tested for their ability to dye UHMWPE fibers. The dyeing study showed visibly darker fibers from the modified dye structures in comparison to the D&C Violet 2 prototype. Overall the C-4 substituted dyes showed darker coloration of the fibers and in general showed lower dye release levels during extractions, making them the preferred choices for PE sutures. All synthesized dyes were also tested under a modified Ames protocol using strain YG1041 both with and without S9 enzyme activation and none of the dyes showed mutagenicity. Poly dyes were also examined for PE sutures coloration through mass coloration. Four yellow anthraquinone polymeric dyes and the group of monomer dyes were incorporated into PE films pressed from the corresponding powder. Most of the polymeric dyes afforded no detectable color following extractions, except for the dye X26669-91 from the Weaver Dye Library. On the other hand, the monomeric dyes were more readily extracted from the films, probably because of the lower crystallinity of the polymer. These films would have a higher ability to swell in the extraction media which leads to the removal of the dyes from the polymer matrix. For UHMWPE fibers 6 new dyes were identified, synthesized and applied in a manner which led to sufficient coloration and small amounts of extracted dye under physiological conditions. The use of polymeric dyes in mass coloration also showed the ability to color PE films through a mass coloration process with little to no dye leaching. © Copyright 2019 by Hannah Kolell All Rights Reserved Hydrophobic Disperse and Polymeric Dyes for the Coloration of UHMWPE Medical Sutures by Hannah Joy Kolell A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the degree of Master of Science Textile Chemistry Raleigh, North Carolina 2019 APPROVED BY: _______________________________ _______________________________ Dr. Harold S. Freeman Dr. Richard Kotek Committee Chair _______________________________ _______________________________ Dr. Lisa Parrillo-Chapman Dr. Malgorzata Szymczyk External Member BIOGRAPHY Hannah Kolell was born in Menomonee Falls, WI and lived there until she earned her Bachelor of Science Degree in Biochemistry with a minor in Mathematics from Valparaiso University in spring of 2017. During her time at Valparaiso she studied abroad in Cambridge, England. She also participated in a summer REU program at the University of Southern Mississippi where she worked on polymer synthesis for a medical application. When it came time to decide on her next step, her love for textiles and sewing as well as for chemistry made the textile chemistry field a perfect fit and combination of these two interests. The pursuit of this field brought her to studying for a masters at North Carolina State University at the Wilson College of Textiles. Under the direction of Dr. Harold Freeman, she developed an interest in dyes and color science. She has enjoyed her time in North Carolina through hiking, beach trips, and exploring the city of Raleigh. ii ACKNOWLEDGMENTS I would first like to thank Dr. Harold Freeman for his continued guidance and knowledge throughout the project. I would also like to thank Dr. Malgorzata Szymczyk for her expertise in the lab and help with the dye synthesis and purification. I also thank the other members of my committee, Dr. Richard Kotek and Dr. Lisa Chapman for their helpful suggestions, advice, and availability. Dr.Gisela Umbuzeiro, Judy Elson, Birgit Andersen, Dr. Hanna Gracz, and Danielle Lehman were all essential for laboratory and instrumental studies. Personally, I would like to thank my fellow graduate students for support and I am so glad to have met and spent time with you all. I cannot say that I would be the chemist that I am today without Megan Cullinan, and I would specifically like to acknowledge her part in the completion of this research. I cannot express enough how thankful I am for the support that I have received from my parents to pursue this as well as from my siblings and friends who took the time to visit me in North Carolina during my time here. iii TABLE OF CONTENTS LIST OF TABLES ........................................................................................................................ vi LIST OF FIGURES ..................................................................................................................... vii Chapter 1: Literature Review and Background ....................................................................... 1 1.1. Polyethylene ...................................................................................................................... 1 1.1.1. Dyeability of Polyethylene ...................................................................................... 2 1.2. Medical Sutures ................................................................................................................ 5 1.2.1. FDA approved dyes used for sutures ....................................................................... 7 1.3. Extraction studies ............................................................................................................. 9 1.4. Mutagenicity and aquatic toxicity studies...................................................................... 10 1.5. Proposed dye structures ................................................................................................. 15 1.5.1. Long alkyl chains for dyeing improvement ........................................................... 16 1.5.2. Target dyes ............................................................................................................. 21 1.6. Polymeric colorants ....................................................................................................... 23 1.6.1 Proposed polymeric dye structures ......................................................................... 24 1.6.2. Mass coloration ...................................................................................................... 26 Chapter 2: Experimental ........................................................................................................... 28 2.1. General ........................................................................................................................... 28 2.1.1. Materials ................................................................................................................ 28 2.1.2. Instruments ............................................................................................................. 29 2.2 Synthesis of dyes............................................................................................................. 31 2.2.1. Mono-azo dyes ....................................................................................................... 31 2.2.2. Mono-anilino-substituted anthraquinone dyes ....................................................... 32 2.2.3. Di-anilino-substituted anthraquinone dyes ............................................................ 33 2.3. Fiber dyeing experiments ............................................................................................... 34 2.4. Mass coloration of PE films ........................................................................................... 35 2.5. Microscopy .................................................................................................................... 35 2.6. Extraction studies ........................................................................................................... 35 2.7. Mutagenetic and toxicity studies ................................................................................... 36 Chapter 3: Results and Discussion ........................................................................................... 37 3.1. Mono-azo and Anthraquinone dyes ............................................................................... 37 3.1.1. NMR spectra of dyes ............................................................................................. 37 3.1.2. Mass Spectrometry of dyes .................................................................................... 51 3.1.3. HPLC of crude dye mixtures ................................................................................