The University of Southern Mississippi The Aquila Digital Community Dissertations Fall 2019 Adsorption of Polyisobutylene-Based Dispersants onto Carbon Black Travis Paul Holbrook University of Southern Mississippi Follow this and additional works at: https://aquila.usm.edu/dissertations Part of the Polymer Chemistry Commons Recommended Citation Holbrook, Travis Paul, "Adsorption of Polyisobutylene-Based Dispersants onto Carbon Black" (2019). Dissertations. 1718. https://aquila.usm.edu/dissertations/1718 This Dissertation is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Dissertations by an authorized administrator of The Aquila Digital Community. For more information, please contact [email protected]. ADSORPTION OF POLYISOBUTYLENE-BASED DISPERSANTS ONTO CARBON BLACK by Travis Paul Holbrook A Dissertation Submitted to the Graduate School, the College of Arts and Sciences and the School of Polymer Science and Engineering at The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Approved by: Dr. Robson F. Storey, Committee Chair Dr. Sarah E. Morgan Dr. Yoan C. Simon Dr. William L. Jarrett Dr. Jeffrey S. Wiggins ____________________ ____________________ ____________________ Dr. Robson F. Storey Dr. Derek L. Patton Dr. Karen S. Coats Committee Chair Director of School Dean of the Graduate School December 2019 COPYRIGHT BY Travis Paul Holbrook 2019 Published by the Graduate School ABSTRACT The formation of carbonaceous by-products (e.g. soot) during the operation of an internal combustion engine is unavoidable and the aggregation of this soot leads to deleterious effects including abrasive wear of the engine, increased oil viscosities, and sludge deposition. Dispersants, which are composed of a hydrophobic tail and a polar headgroup, are used as oil additives to aid in the suspension and stabilization of the soot particles. Polyisobutylene succinimide (PIBSI) is the most well-studied class of dispersants and is characterized by a linear architecture and polyamine headgroup that interacts with soot by acid-base and dipole-dipole interactions. As such, there remains a lack in understanding on the effect of dispersant architecture and alternative dispersant- soot interactions and the governing characteristics of these interactions. In the first project, we synthesized a library of polyisobutylene (PIB)-based dispersants with varying architecture. Linear dispersants were prepared via living cationic polymerization and grafted dispersants by the acid-catalyzed cleavage/alkylation of butyl rubber. Comb dispersants were prepared from the alternating copolymerization of vinyl-ether PIB (VE-PIB) macromers with maleic anhydride where the rate of copolymerization was found to be heavily influenced by molecular weight of the VE-PIB macromer. The affinity and degree to which comb and grafted dispersants adsorbed to carbon black was found to be similar whereas a linear dispersant exhibited reduced affinity yet increased adsorption capacity. In the second project, we investigated the effect of PIB-based dispersants containing exclusively non-nucleophilic nitrogen in addition to how π-π interactions can be leveraged for the adsorption of dispersants. Linear PIB was functionalized with 1-(2- i aminoethylpiperazine) and was subsequently functionalized with cyclic anhydrides of varying degrees of aromaticity. Metal corrosion and fluoroelastomer compatibility indicated that dispersants with non-nucleophilic nitrogen were less aggressive while providing a greater degree of total base number in comparison to PIBSI dispersants. A critical size of at least two terminal aromatic rings was found to be able to leverage advantageous π-π interactions between dispersants and carbon black for increased adsorption. In the third project, we investigated cation-π interactions between carbon black and ionic-liquid terminated PIB (PIB-IL) dispersants. Interaction of the nitrogenous cation with the quadrupole moment of the aromatic surface provided for strong non- covalent interactions which can be used as an alternative mechanism for adsorption. A library of PIB-IL dispersants was prepared through the quaternization of aromatic amines and metathesis of counterions. The characteristics of PIB-IL micellization (Nagg, CMC, Mmicelle, Rh) were heavily influenced by anion hydrophobicity whereas PIB-IL adsorption to carbon black was dictated by the molar volume of the cation. The fourth project, which was of an alternative focus, investigated Diels-Alder crosslinked PIB networks which were prepared from multifunctional PIB-Furan and PIB- Maleimide macromers utilizing the acid catalyzed cleavage/alkylation of butyl rubber. Thermal stability, including decomposition temperature and retro Diels-Alder temperatures (TRDA) were independent of macromer choice however the viscoelastic properties were heavily influenced. Recyclability was demonstrated by remolding and recasting of destroyed networks at elevated temperatures and a slight hysteresis in mechanical properties was observed as compared to original networks. ii ACKNOWLEDGMENTS First and foremost, I would like to thank my advisor, Dr. Robson Storey, for his persistence in my recruitment to The University of Southern Mississippi, the School of Polymer Science and Engineering, and the Storey Research Group. Whether it was my decision to come to graduate school or stay once I was here, you let me know that the door was always open and let me make that decision for myself rather than push me one direction or the other. You allowed me to exercise creativity in my research, develop and explore ideas of my own, and pushed me to think outside-of-the-box. I was given the opportunity to mature as a scientist and develop technical and professional skills under your tutelage and by your willingness to provide me with plenty of occasions to grow including internship and research conference opportunities. From an REU who’s name you thought was Justin to today, it has been a pleasure to work for you and work with you these past five years and I thank you for giving me that opportunity. I would like to thank my committee members, Dr. William Jarrett, Dr. Sarah Morgan, Dr. Yoan Simon, and Dr. Jeffrey Wiggins for their assistance and guidance during my graduate career. I would like to acknowledge the Wiggins, Morgan, and Thames-Rawlins Research Group groups who have been vital to my research by providing me access to and assistance with instruments I otherwise would not have been able to use. I would like to thank Melanie Heusser for being a terrific administrative assistant who I could always count on to help solve any administrative problems that I had. I would also like to thank Charles Collen and Jeff Hollingsworth at the Fisher Chemical Store Room for putting up with my incessant emails about ordering chemicals as well as providing great friendship over the years. iii Furthermore, I would like to acknowledge Chevron Oronite LLC for providing funding for much of the research with this dissertation and setting me off on the path of investigating dispersants. Specifically, I wish to thank Dr. Georgeta Masson, who provided invaluable industrial expertise and was a pleasure to collaborate with over the year years, as well as Dr. Kirk Nass and Dr. Michael Driver, who fostered a welcoming atmosphere and a challenging internship experience for me. Lastly, I would like to acknowledge the Storey Research Group lab members, past and present, who made coming into work each day an exciting, interesting, unpredictable and fun time. I could not have hand-chosen a better group of individuals to work with and I thank every one of you for making graduate school an enjoyable and memorable experience. For this, I would like to recognize Dr. Mark Brei, Dr. Garrett Campbell, Dr. Bin Yang, Dr. Corey Parada, Dr. Hunter Cooke, Morgan Heskett, Tom Wu, Logan Dugas, Harrison Livingston and Grace Parker. iv DEDICATION I would like to dedicate this dissertation and all the time, effort, and sacrifice that went into it to those who have supported me during my time at Southern Miss. To my family and friends, I can honestly say I would not have been able to finish without you to keep me sane through the years. You might not understand much of the research in this document and I may have had to explain more than once what exactly a polymer is, but you understood that it was important to me and have supported me throughout the years. This includes my Dad and Mom, Chic and Lisa, who have always pushed me to be the best that I can possibly be as a student and more importantly, as a person. Thank you for teaching me what the true meaning of family is and for raising me to be the man that I am today. My sisters, Holly and Hannah, who I know have and always will be there for me and have believed in me even when I didn’t believe in myself. My brother, Chad, who I know is always with me no matter what and helped kinder my competitive spirit when we were younger which has brought me to where I am. My nieces, Greer and Austin, who are just the cutest little girls and who I can’t wait to see grow up and do amazing things. My grandpa and grandma, Roland and Betty, who helped motivate me to attend and finish graduate school and who always made sure to make time for a breakfast when I came back home. To my friends back home, James, Cody, and Josh, thank you for always being your goofball selves and giving me an outlet from graduate school. And to my wonderful girlfriend, Ashleigh, who I met in the program during our first year here and has been nothing short of amazing to me. Time flies by so fast and it seems like only yesterday we were just meeting each other in the 2nd floor conference v room or drawing mechanism for Dr. McCormick’s class on the whiteboard. Graduate school has been a difficult ride and having someone there with me through the journey, who understood the challenges, was irreplaceable.