Applicability of Catalytic in Situ Olefin Polymerization in Wood Technology

Applicability of Catalytic in situ Olefin Polymerization in Wood Technology Dissertation with the aim of achieving a doctoral degree at the Institute of Wood Science Department of Biology & Institute of Technical and Macromolecular Chemistry Department of Chemistry Faculty of Mathematics, Informatics and Natural Sciences Universität Hamburg Submitted by Julius Gurr Hamburg 2020 1st Supervisor: Prof. Dr. Andreas Krause Universität Hamburg Fachbereich Biologie Institut für Holzwissenschaften Leuschnerstraße 91c 21031 Hamburg 2nd Supervisor: Prof. Dr. Gerrit A. Luinstra Universität Hamburg Fachbereich Chemie Institut für Technische und Makromolekulare Chemie Bundesstraße 45 20146 Hamburg Submission: 21.12.2020 Disputation: 04.05.2021 Dedicated to my family Acknowledgement The study at hand is the result of a collaboration between the Institute of Wood Sciences and the Institute of Technical and Macromolecular Chemistry, both of the University of Hamburg. First of all I would like to thank my doctoral advisor Prof. Dr. Andreas Krause for his encouragement to stay on as a doctoral student, the enormous freedom he gave me, as well as his kindness and trust. I have learned a great deal from him and it has been an invaluable experience to me. I would also like to thank my second thesis examiner Prof. Dr. Gerrit A. Luinstra for the opportunity to perform my studies at his facilities as well as for his support and scientific advice. Prof. Dr. Bodo Saake and Prof. Dr. Elizabeth Magel not only agreed to be part of my defense commission, but accompanied me during my undergrad and postgrad studies as highly dedicated and valued teachers. I would like to express my gratitude for all their effort, not only towards me but all wood science students. I would like to thank the "Östad-Gang" Dr. Oliver Mertens, Dr. Goran Schmidt und Dr. Martin Nopens for their friendship, moral support and great time. I would like to thank my TMC office fellows Sebastian Eller, Daniel Griebe and Dirk de Boer for their friendship, endless support and patience. Special thanks go to my friends, colleagues and supporters Sylvia Diestel, Bettina Stef- fen, Dr. Julien Navarro and Yannick Wencke. I would also like to thank my student as- sistants Adriana Molina Benitez and Dominik Radsziwill for their help with the lab work. I consider myself extremely lucky for having had the opportunity of working alongside a long list of admirable colleagues. From the Institute of Wood Sciences and the Thuenen Institute for Wood Research I would like to thank Johannes Beruda, Dörte Bielenberg, Stephanie Warsow, Daniela Nissen, Regina Schröter, Sergej Kaschuro, Tanja Potsch and Gabrielle Circelli for their years of help and support. I would also like to thank all of them for their pleasant company and the enjoyable time we spent together. A special thanks goes to the library team, namely Astrid Stilke and Sandra Jacobi, who have wielded their magic in finding lost treasures of literature countless times. From the Institute of Technical and Macromolecular Chemistry I would like to thank Dr. Robert Meyer, Dr. Felix Scheliger, Dr. Werner Pauer, Kathleen Pruntsch, Peter Harry, Stefan Bleck, Ansgar Weidner and Josef. Further members of the Chemistry Department that have my sincere gratitude are Claudia Wackendorff, Dr. Ulrich Riederer and Andreas Kornowski. Special thanks go to Sophie Füchtner from the University of Copenhagen for her friendship and her support in Raman microscopy. I would also like to thank her whole team for the kind reception and atmosphere. - I - From the Zoology of the University of Hamburg I would like to thank Renate Walter, Sabine Gaude and Dr. Frank Friederich for their support in electron microscopy. From the Heinrich-Pette-Institute Hamburg I would like to thank Dr. Rudolph Reimer for his support in cryo-ultra-microtome sectioning. Furthermore, I would like to express my sincere gratitude to Prof. Dr. Jörg B. Ressel and Prof. Dr. Udo Mantau for the decades of dedication they have put into the education of Wood Science students. I have been fortunate to have had such excellent teachers and they have my deepest appreciation. Many more people have been involved, have supported me or have been companions along the way. They all have my deepest gratitude. Last but not least, I would like to thank my family and my wife for their continuous moral support, encouragement and love. Without them I would not be where or who I am today. I will be forever grateful. Hamburg, December 2020 - II - Abstract This study investigates the introduction of metallocene olefin polymerization methods into the field of wood science. For the first time, catalytic ethylene polymerization was applied to bulk wood, in order to perform lumen filling as measure of physical preserva- tion. This represents, in addition, the first demonstration of successful catalytic olefin polymerization within macro-porous solids. In addition, this study represents the most comprehensive discussion to date on catalytic olefin polymerization in combination with wood or cellulose. The utilized, highly specialized catalytic system consisted of a metallocene catalyst and aluminum alkyl cocatalyst. Using wood bound water in combination with trimethylaluminum as a more economical substitute for prefabricated methylaluminoxane in metallocene catalysis in the production of wood polyethylene composites has been proven highly successful and recommenda- ble. Precise moisture management has been shown to be paramount for the successful and repeatable in situ synthesis of an active aluminoxane species. Vacuum drying experiments and subsequent coulometric Karl Fischer Titration showed that the moisture management of pine wood flour, beech wood flour and microcrystalline cellulose is fea- sible. By varying the drying time, temperature and pressure, the moisture content may be fine-tuned. Gas titration experiments revealed that the degree of hydrolysis of trimethylaluminum with wood bound water can be fine-tuned by moisture management. The formation of a catalytically active aluminoxane species by partial hydrolysis of trimethylaluminum with wood bound water was proven by successful polymerization experiments. Catalytic activities were comparable to those of prefabricated methylaluminoxane. Moisture management was shown to influence catalytic activities. The utilization of wood flour containing residual moisture was shown to lead to enhanced filler encap- sulation. Material characterization showed that molecular weights of the resultant poly- mers increased, offering the opportunity to produce higher molecular weight polyethylene at lower temperatures. Results also suggest that the single-site character of the catalyst is preserved and that the molecular structure of the resultant polymer remains relatively similar. Proof of concept of the macro-confined metallocene catalyzed polymerization of ethylene has been demonstrated successfully. The impregnation of solid wood samples with a catalyst was investigated by energy dispersive X-ray spectroscopy. Soaking samples in pure liquid trimethylaluminum as well as alternating pressure impregnation led to the most homogeneous distribution. A variety of microscopic techniques were employed to investigate successful polymerization within the macro-confinement of the wood cell lumen. Clusters of cells with lumen entirely filled were observed repeatedly. The polyethylene nature of the materials filling the lumen were proven with energy dispersive X-ray spectroscopy and Raman-microscopy. Promising areas of future research regarding basic research questions, potential alter- native processes as well as novel material concepts and applications are outlined. - III - Kurzfassung Diese Studie untersucht die Anwendbarkeit von Metallocen-Olefin-Polymerisationsver- fahren im Bereich der Holzforschung. Erstmals wurde die katalytische Ethylenpolymeri- sation auf Vollholz angewandt, um eine neuartige Lumenfüllung als Maßnahme des phy- sikalischen Holzschutzes durchzuführen. Diese Studie stellt somit den ersten Nachweis erfolgreicher katalytischer Olefinpolymerisation innerhalb makro-poröser Feststoffe dar. Darüber hinaus beinhaltet diese Studie die bisher umfassendste Diskussion über die Heterogenisierung von Polymerisationskatalysatoren auf Cellulosesubstraten zur an- schließenden Mischpolymerisation von Olefin-basierten Verbundmaterialien. Das einge- setzte, hochspezialisierte Katalysatorsystem bestand aus einem Metallocen-Katalysator und einem Aluminiumalkyl-Cokatalysator. Die Verwendung von holzgebundenem Wasser in Kombination mit Trimethylaluminium als kostengünstiger Ersatz für vorgefertigtes Methylaluminoxan in der Metallocenkata- lyse bei der Herstellung von Holz-Polyethylen-Verbundwerkstoffen hat sich als sehr er- folgreich und empfehlenswert erwiesen. Es hat sich herausgestellt, dass ein präzises Management der Holzfeuchte für die erfolgreiche und wiederholbare in situ Synthese einer katalytisch aktiven Aluminoxan-Spezies von entscheidender Bedeutung ist. Vaku- umtrocknungsversuche mit anschließender coulometrischer Karl-Fischer-Titration zeigten, dass die präzise Regulierung der Materialfeuchten von Kiefernholzmehl, Buchen- holzmehl und mikrokristalliner Cellulose möglich ist. Die Variation von Trocknungszeit, Temperatur und Druck ermöglichen die Kontrolle über Feuchtigkeitsgehalte in den katalytisch relevanten Bereichen. Gastitrationsexperimente zeigten, dass der Grad der Hyd- rolyse von Trimethylaluminium durch Reaktion mit holzgebundenem Wasser ebenfalls durch

Load more