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Spontaneous small molecule migration via reversible Michael reactionsLewandowska, Urszula January 2013 (has links)
Small molecule walkers developed to date take advantage of the reversibility of dynamic covalent bond formation to transport molecular fragments along molecular tracks using both diffusion processes and ratchet mechanisms. However, external intervention (the addition of chemical reagents and/or irradiation with light) is required to mediate each step taken by the walker unit in systems reported so far. In this Thesis, the first synthetic small molecule able to walk back-and-forth upon an oligoethylenimine track without external intervention via intramolecular Michael and retro- Michael reactions is described. The 1D random walk is highly processive and exchange takes place between adjacent amine groups in a stepwise fashion. The walker is used to perform a simple task: quenching of the fluorescence of an anthracene group situated at one end of the track as a result of the walking progress. In the presence of excess of base, the molecule preferentially ‘walks’ towards the favoured final foothold of tracks of increasing length and it is possible to monitor the population of all or a few positional isomers over time. In each case the molar fraction of walkers reaching the final foothold is determined quantitatively by 1H NMR. Control over the rate of exchange is achieved by varying the amount of base added. The dynamic migration of a small molecule upon the track is a diffusion process limited to one dimension and as such can in principle be described using the one dimensional random walk. Chapter I identifies a set of fundamental walker characteristics and includes an overview of the DNA-based and small molecule transporting systems published to date. Chapter II describes the inspiration for this work and model studies which lay the groundwork for the research presented in this thesis. The initial track architecture and optimisation of reaction conditions are demonstrated using a simple model compound which then led to the development and a detailed investigation of a first synthetic small molecule able to walk upon an oligoethylenimine track without external intervention. Chapter III presents a modified synthetic route towards the desired walker-track architectures and a comprehensive investigation of the dynamic properties of a series of tracks of increasing length upon which the walker migrates in a unidirectional fashion. The Outlook contains closing remarks about the scope and significance of the presented work as well as ideas for the design of novel small-molecule walkers, some of which are well under way in the laboratory. Chapter II (with the exception of model studies included at the beginning of the chapter) is presented in the form of article that has recently been published. No attempt has been made to re-write this work out of context other than merging content of the article with the supplementary information published together with the article. Chapter II is reproduced in the Appendix in its published format.
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IMOBILIZAÃÃO DE LIPASE DE Candida antarctica TIPO B EM TOYOPEARL / Immobilization of Candida antarctica type B lipase in ToyopearlElizabete AraÃjo Carneiro 28 August 2007 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O objetivo deste trabalho foi estudar a imobilizaÃÃo da lipase de Candida antarctica tipo B (CalB) atravÃs de ligaÃÃo covalente utilizando a resina hidrofÃlica Toyopearl como suporte. Avaliaram-se vÃrios protocolos de ativaÃÃo, utilizando como agentes ativantes: glicidol, glutaraldeÃdo e etilenodiamina (EDA), e seu efeito na atividade hidrolÃtica do biocatalisador obtido. A atividade hidrolÃtica dos derivados foi avaliada pela hidrÃlise do butirato de para-nitrofenila (PNPB) e utilizou-se como reaÃÃo de esterificaÃÃo, a sÃntese do butirato de butila, empregando Ãcido butÃrico e butanol como substratos. O suporte foi previamente caracterizado pela obtenÃÃo de imagens por microscopia eletrÃnica de varredura (MEV), difratogramas de raio-X (DRX) e espectros de infravermelho (FTIR). A Ãrea superficial e a porosidade do suporte foram avaliadas pelo mÃtodo BET. Determinaram-se a concentraÃÃo de proteÃna e a atividade enzimÃtica do sobrenadante antes e apÃs os processos de imobilizaÃÃo. O melhor resultado de atividade hidrolÃtica da enzima imobilizada foi de 894,17  43,29 U/g de suporte, utilizando o suporte Toyopearl-Glioxil-EDA-GlutaraldeÃdo (Toyo-GEG). Este valor de atividade foi 1,56 vezes maior que o obtido para o derivado comercial Novozym 435. A influÃncia de diferentes concentraÃÃes de proteÃna foi avaliada e observou-se a saturaÃÃo do suporte com uma concentraÃÃo de 40 mg/g e 2238,25  27,33U/g de atividade. A influÃncia dos tempos de incubaÃÃo na imobilizaÃÃo indicou que longos tempos de imobilizaÃÃo acarretam na diminuiÃÃo da atividade hidrolÃtica dos biocatalisadores. Nos estudos de estabilidade tÃrmica a 60 C, conseguiu-se um elevado grau de estabilizaÃÃo para o derivado, com estabilidade tÃrmica superior a da enzima solÃvel. Para o derivado obtido com 72 horas de imobilizaÃÃo o fator de estabilizaÃÃo em relaÃÃo à enzima solÃvel e ao derivado comercial, respectivamente, foi de 694,56 e 12,74. Quanto à estabilidade operacional, apÃs o sÃtimo ciclo de sÃntese do butirato de butila, o derivado Toyo-GEG reteve em torno de 76 % de sua atividade inicial. / The objective of this work was to study the immobilization of Candida antarctica type B lipase (CalB) by covalent bond using hydrophilic resin named Toyopearl as a support. The influence of activation agents (glycidol, glutaraldehyde and ethylenediamine) in the hydrolytic activity of the biocatalyst was investigated. The enzyme preparations were tested in the hydrolysis of para-nitrophenyl butyrate (PNPB) and in an esterification reaction, butyl butyrate synthesis from butyric acid and butanol. The support was previously characterized by scanning electronic microscopy (SEM), Xray diffraction (DRX) and Fourier transform infra red (FTIR). Superficial area and porosity were evaluated using BET method. Protein concentration and enzymatic activity in the supernatant were determined before and after immobilization process. Best results of hydrolytic activity were obtained using the enzyme immobilized in Toyopearl-Glyoxyl-EDA-Glutaraldehyde (Toyo-GEG), 894.17  43.29 U/g of support, which is 1.56-fold higher than the hydrolytic activity of Novozym 435. The influence of different loadings of protein and the incubation time in the immobilization were also studied. The saturation of support was observed with a load of 40 mg/g of support with 2238.25  27.33 U/g. A decrease in the hydrolytic activity of enzyme preparations was observed for long incubation times. However, thermal stability studies at 60 C, showed that this parameter was important for enzyme stabilization. Thermal stabilization by immobilization was achieved and the immobilized enzyme was more thermal stable than the soluble enzyme. The immobilized lipase prepared at incubation time of 72 hours was 694.59-fold more stable than soluble enzyme and 12.74 -fold than Novozym 435. In organic medium, cycles of synthesis of butyl butyrate was chosen to quantify operational stability. After the seventh cycle, Toyo-GEG retained around 76 % of the initial activity.
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Studies on Asymmetric Hetero-Michael Addition Utilizing Various Modes of Organocatalytic Activation / 有機分子触媒による様々な活性化を利用した不斉ヘテロマイケル付加反応に関する研究Fukata, Yukihiro 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19725号 / 工博第4180号 / 新制||工||1645(附属図書館) / 32761 / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 松原 誠二郎, 教授 中尾 佳亮, 教授 杉野目 道紀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Studies of multicomponent assembliesLong, Samuel Reid 03 March 2014 (has links)
This dissertation is divided into three major sections (one on dendrimers, one on tripodal metal ligands and one on a research oriented chemistry curricula) with a primary focus on different types of multicomponent assemblies. In the first chapter, a system is described that used a multicomponent assembly of AT-PAMAM dendrimers and an indicator, carboxyfluorescein, to detect and identify various polyanions at a low micromolar concentration. The system was able to successfully differentiate twelve anions, many of biological interest, including three tricarboxylates. The tricarboxylates were differentiated based primarily on the regiochemistry of the anionic groups.
In the second chapter, further studies with AT-PAMAM dendrimers were carried out to provide some understanding of the thermodynamic origins of binding. Utilizing isothermal titration calorimetry, the binding of the dendrimers to large polyanionic dendrons with increasing numbers of charges was studied. Through these studies, the thermodynamic values of the binding events were obtained allowing us to explore the properties of the dendrimers. The cooperativity of the system was measured, and primarily negative cooperativity determined by the entropic contributions was uncovered. As the dendrimers increased in size, the thermodynamic origins of binding were determined to a greater extent by the entropy of binding.
In the third chapter, a novel dynamic ligand system for metal binding is described. In the presence of a metal salt, a heterocyclic aldehyde and a secondary amine with two heterocyclic arms reversibly condense to form a hemiaminal with a tripodal metal binding site. This chapter describes studies on the metal binding ability, the variety of metals that will lead to this formation, the effects of anions and the range of aldehydes that can be used are described. Furthermore, the system’s reversibility was explored. Finally, the use of a bistriazole secondary amine was explored. The modular nature of triazole formation could lead to the introduction of additional functionalities.
The fourth chapter discusses how the novel ligand system could be used to study the enantiomeric excess (ee) of chiral thiols. Based upon the system’s ability to form a stable hemiaminal thioether, a CD signal could be generated that is proportional to the amount of a particular enantiomer in solution. Using this system, a calibration curve relating CD signal and ee can be generated giving the ee of an unknown solution.
In the final chapter, a look at the Freshman Research Initiative will be carried out with a focus on the ability to teach basic skills in an introductory laboratory through research. Four different skills or techniques will be explored through three different FRI streams,x and how they teach the four skills. Finally, analysis of the success of the program, particularly students’ success in the next laboratory course in the sequence, is discussed, and a model for adopting this type of teaching at other universities is given. / text
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Covalent Labeling and Functional Analyses of Target Proteins in Living Cells Using the Interaction of His tag/Ni(II)-NTA Pair / His タグ/Ni(II)-NTA ペア間相互作用を利用した生細胞での標的タンパク室の共有結合ラベルとその機能解析Uchinomiya, Shohei 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18303号 / 工博第3895号 / 新制||工||1598(附属図書館) / 31161 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 濵地 格, 教授 森 泰生, 教授 跡見 晴幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
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Nucleic acid assembly, polymerization, and ligand bindingEngelhart, Aaron Edward 08 February 2012 (has links)
In the past 30 years, the discovery of capabilities of nucleic acids far beyond their well-known information-bearing capacity has profoundly influenced our understanding of these polymers. The discovery by the Cech and Altman labs that nucleic acids could perform catalytic functions, coupled with the Gold and Szostak groups’ demonstration of the de novo evolution of nucleic acids that bind arbitrary ligands, has resulted in a proliferation of newfound roles for these molecules. Nucleic acids have found utility in both engineered systems, such as aptamer therapeutics, as well as in newly appreciated roles in extant organisms, such as riboswitches. As a result of these discoveries, many have pondered the potential importance of the dual (catalytic and informational) roles of nucleic acids in early evolution. A high-yielding synthetic route for the nonenzymatic polymerization of nucleic acids, based on the aqueous self-assembly of their components, would provide a powerful tool in nucleic acid chemistry, with potential utility in prebiotic and contemporary nucleic acid systems alike – however, such a route remains elusive. In this thesis, I describe several steps towards such a synthetic route. In these systems, a nucleic-acid binding ligand drives the assembly of short DNA and RNA duplexes, promoting the production of long nucleic acid polymers, while suppressing the production of short, cyclic species. Additionally, the use of a reversible covalent linkage allows for the production of long polymers, as well as the incorporation of previously cyclized products into these polymers. I also report several explorations of novel base pairings, nucleic acid-ligand interactions, and nucleic acid-ion interactions that have informed our studies of self-assembling nucleic acid systems.
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Deposition And Covalent Immobilization of Porphyrin And Maleimide On A Si(111) SurfaceLovrek, Kristina 17 July 2020 (has links)
Eine Studie zur kovalenten Immobilisierung einiger Porphyrinderivate und einer p-Maleimidophenyl-Spezies (p-MP) auf der Si(111)-Oberfläche wird vorgestellt. Hierbei lag der Schwerpunkt auf der Untersuchung des Einflusses von Reaktionsparametern auf die Abscheidung und die Qualität organischer Schichten. Die dünnen Schichten werden mittels nasschemischer Methoden abgeschieden. Die hergestellten Strukturen werden mit einer Vielzahl oberflächensensitiver Messtechniken wie der IR-Ellipsometrie, der XPS-, der SEIRA- und der IR-Reflexionsspektroskopie analysiert. Alle Abscheidungen in dieser Arbeit werden in situ durchgeführt, zusätzlich zu den ex situ Reaktionen, um das Verständnis der Filmwachstums- und Depositionsgeschwindigkeiten zu erhalten. Bei der Untersuchung der Porphyrin-Dünnschichten lag der Fokus auf den synthetische Bedingungen der Materialabscheidung. Die Lösungsreaktionen zeigen, dass die Reaktion mit dem voraktivierten Porphyrinderivat zu einer besseren Ausbeute führt als mit dem in situ aktivierten Porphyrin. Wenn diese Reaktion jedoch unter Verwendung des Schicht-für-Schicht-Abscheidungsprinzips auf die Oberfläche übertragen wird, findet die Reaktion mit den oberflächengebundenen Aminosilanmolekülen mit einer viel langsameren Geschwindigkeit statt als die gleiche Reaktion in Lösung. Es wird ein alternativer Syntheseansatz vorgeschlagen, bei dem das Produkt in Lösung hergestellt und dann auf dem oxidierten Si-Substrat abgeschieden wird. Eine weitere in situ-Studie zum p-MP-Elektropfropfen auf der H-terminierten Si(111)-Oberfläche liefert Details zur Dünnschichtbildung im monolagigen und im sub-monolagigen Bereich. Die spontane Pfropfung von p-MP wird ebenfalls in situ überwacht. Es wurde festgestellt, dass die Bildung einer Monoschicht während der stromlosen Abscheidung länger dauert als bei einer elektrochemischen Abscheidung. Als Alternative zum Radikalmechanismus wird ein kationischer Mechanismus vorgeschlagen. / A study on the covalent immobilization of a couple of porphyrin derivatives and a p-maleimidophenyl species (p-MP) on Si(111) surface is presented to investigate how do reaction parameters influence the deposition and the quality of organic layers. The thin films are deposited with “wet chemistry” methods. The prepared structures are analyzed with a variety of surface sensitive techniques, namely, IR ellipsometry, XPS, SEIRA, and IR reflection spectroscopy. All depositions in this work are conducted in situ, in addition to the ex situ reactions, to gain an understanding of the film growth and deposition rates. The study on porphyrin thin films focused on the synthetic conditions of material deposition. Solution reactions indicate that the reaction with the pre-activated porphyrin derivative leads to a better yield than with the in situ-activated porphyrin. However, when this reaction is transferred to the surface by using the layer-by-layer deposition approach, the reaction with the surface-bound aminosilanes molecules takes place at a much slower rate than the same reaction in solution. An alternative synthetic approach, where the product is prepared in solution and then deposited on the oxidized Si substrate, is proposed. A parallel in situ study on p-MP electrografting on the H-terminated Si(111) surface provides details on the thin film formation in a monolayer and a sub-monolayer regime. The spontaneous grafting of p-MP is also monitored in situ. It was found that the formation of a monolayer during the electroless deposition takes longer than an electrochemical deposition. A cationic mechanism is proposed as an alternative to a radical mechanism.
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Synthèse, caractérisation et étude du comportement à la déshydratation par diffraction des rayon X sur monocristal et poudre, de quelques composés supramoléculaires à base de métallo-tectons ioniques / Synthesis, Characterization and Study of Behavior with Single Crystal and Powder X-rays Diffraction Analysis during the Dehydration Process of some Supramolecular Compounds built with Ionic Metallo-tectonsKenfack Tsobnang, Patrice 20 November 2014 (has links)
Ce travail réalisé dans le cadre de l’initiative africaine de l’IUCr porte sur l’étude structurale par diffraction des rayons X de quelques architectures élaborées par association, via des interactions faibles, des anions {[M(C2O4)3]3-,M = Cr, Fe} et des cations complexes à base de la 2-picolylamine (amp) métaux de transition (Co2+, Cu2+ et Mn2+). L’architecture à base de l’ion Co2+ est bidimensionnelle et présente des feuillets ondulés constitués de chaines bimétalliques de chiralité différente où les deux ions complexes ([Cr(C2O4)3]3- et [Co(amp)3]3+ ) sont connectés par des liaisons hydrogène. Ces feuillets hébergent des molécules d’eau qui forment des clusters dodécamèriques aux caractéristiques nouvelles. Le composé déshydraté se réhydrate rapidement dans l’air ambiant et les deux états possèdent des couleurs différentes. Plusieurs cycles de déshydratation-réhydratation n’altèrent pas la qualité cristalline du composé. L’architecture à base des ions Cu2+ possède également des feuillets mais présente une ondulation plus forte que celle de l’architecture au cobalt. Ces couches sont constituées de chaines formées de cations dimériques [Cu2(amp)4Cl]3+ et d’anions {[M(C2O4)3]3-,M = Cr, Fe}. Les deux composés sont iso-structuraux et leur architecture présente des canaux monodimensionnels qui contiennent des molécules d’eau qui forment des clusters hexamèriques. Le composé subit des transitions de phase entre la basse température (100K) et la température de déshydratation (341K) avec une perte de la symétrie. Le composé se réhydrate plus difficilement que celui à base de l’ion cobalt(III). L’ion Mn2+ ne donne pas l’architecture escomptée mais un polymère de coordination nouveau / This work, realized under the IUCr initiative, framework involves the structural study via X-ray diffraction, of some heteromolecular architectures formed by the association through non-covalent bonds, between the tris (oxalato) chromate (III) and tris (oxalato) ferrate (III) anions {[M(C2O4)3]3-, M = Cr, Fe} and the cationic complex of the 2-picolylamine (amp) and transition metal (Co2 +, Cu2 + and Mn2 +). Co2 + ion builds two-dimensional corrugated layers made of bimetallic chiral chains where the two different complex ions ([Cr(C2O4)3]3- and [Co(amp)3]3 +) are connected by hydrogen bonds. These layers, connected by weak hydrogen interactions, host between them, water molecules which build dodecameric clusters having new characteristics. The dehydrated compound has different structure and color and is able to quickly reabsorb water molecules from surrounding to regenerate the initial compound despite that it has no pores. Several cycles of this process do not seriously affect the crystalline quality of this compound. The compound obtained with the Cu2 + ion also has a two-dimensional framework. Their layers are formed between the dimeric cation [Cu2 (amp) 4Cl]3 + and the anion {[M(C2O4)3]3-,M = Cr, Fe}. Both compounds are iso-structural; their frameworks are formed via π - - - π interactions and build 1D channels which contain water molecules forming hexameric clusters. The compound undergoes a phase transition between 100 K and the dehydration temperature (341K). During this dehydration, a loss of symmetry of the compound is recorded and rehydration process is more difficult than for cobalt(III)-framework. The use of Mn2+ ions does not give the expected architecture but a new coordination polymer
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Physico-Chemical Processes during Reactive Paper Sizing with Alkenyl Succinic Anhydride (ASA) / Physikochemische Prozesse während der Reaktivleimung mit Alkenyl-Bernsteinsäure-Anhydrid (ASA)Porkert, Sebastian 27 February 2017 (has links) (PDF)
Sizing (hydrophobization) is one of the most important process steps within the added-value chain of about 1/3rd of the worldwide produced paper & board products. Even though sizing with so-called reactive sizing agents, such as alkenyl succinic anhydride (ASA) was implemented in the paper industry decades ago, there is no total clarity yet about the detailed chemical and physical mechanisms that lead to their performance. Previous research was carried out on the role of different factors influencing the sizing performance, such as bonding between ASA and cellulose, ASA hydrolysis, size revision as well as the most important interactions with stock components, process parameters and additives during the paper making process. However, it was not yet possible to develop a holistic model for the explanation of the sizing performance given in real life application. This thesis describes a novel physico-chemical approach to this problem by including results from previous research and combining these with a wide field of own basic research and a newly developed method that allows tracing back the actual localization of ASA within the sheet structure.
The carried out measurements and trial sets for the basic field of research served to evaluate the stock and process parameters that most dominantly influence the sizing performance of ASA. Interactions with additives other than retention aids were not taken into account. The results show that parameters, such as the content of secondary fibers, the degree of refining, the water hardness as well as the suspension conductivity, are of highest significance. The sample sets of the trials with the major impacting parameters were additionally analyzed by a newly developed localization method in order to better understand the main influencing factors.
This method is based on optical localization of ASA within the sheet structure by confocal white light microscopy. In order to fulfill the requirements at magnification rates of factor 100 optical zoom, it was necessary to improve the contrast between ASA and cellulose. Therefore, ASA was pretreated with an inert red diazo dye, which does not have any impact on neither the sizing nor the handling properties of ASA. Laboratory hand sheets that were sized with dyed ASA, were analyzed by means of their sizing performance in correlation to measurable ASA agglomerations in the sheet structure. The sizing performance was measured by ultrasonic penetration analysis. The agglomeration behavior of ASA was analyzed automatically by multiple random imaging of a sample area of approx. 8650 µm² with a minimum resolution for particles of 500 nm in size. The gained results were interpreted by full factorial design of experiments (DOE). The trials were carried out with ASA dosages between 0% and 0.8% on laboratory hand sheets, made of 80% bleached eucalyptus short fiber kraft pulp and 20% northern bleached softwood kraft pulp, beaten to SR° 30, produced with a RDA sheet former at a base weight of 100 g/m² oven dry.
The results show that there is a defined correlation between the ASA dosage, the sizing performance and the number and area of ASA agglomerates to be found in the sheet structure. It was also possible to show that the agglomeration behavior is highly influenced by external factors like furnish composition and process parameters. This enables a new approach to the explanation of sizing performance, by making it possible to not only examine the performance of the sizing agent, but to closely look at the predominant position where it is located in the sheet structure. These results lead to the explanation that the phenomenon of sizing is by far not a pure chemical process but rather a more physical one. Based on the gained findings it was possible so far to optimize the ASA sizing process in industrial-scale by means of ~ 50% less ASA consumption at a steady degree of sizing and improved physical sheet properties.
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Physico-Chemical Processes during Reactive Paper Sizing with Alkenyl Succinic Anhydride (ASA)Porkert, Sebastian 09 December 2016 (has links)
Sizing (hydrophobization) is one of the most important process steps within the added-value chain of about 1/3rd of the worldwide produced paper & board products. Even though sizing with so-called reactive sizing agents, such as alkenyl succinic anhydride (ASA) was implemented in the paper industry decades ago, there is no total clarity yet about the detailed chemical and physical mechanisms that lead to their performance. Previous research was carried out on the role of different factors influencing the sizing performance, such as bonding between ASA and cellulose, ASA hydrolysis, size revision as well as the most important interactions with stock components, process parameters and additives during the paper making process. However, it was not yet possible to develop a holistic model for the explanation of the sizing performance given in real life application. This thesis describes a novel physico-chemical approach to this problem by including results from previous research and combining these with a wide field of own basic research and a newly developed method that allows tracing back the actual localization of ASA within the sheet structure.
The carried out measurements and trial sets for the basic field of research served to evaluate the stock and process parameters that most dominantly influence the sizing performance of ASA. Interactions with additives other than retention aids were not taken into account. The results show that parameters, such as the content of secondary fibers, the degree of refining, the water hardness as well as the suspension conductivity, are of highest significance. The sample sets of the trials with the major impacting parameters were additionally analyzed by a newly developed localization method in order to better understand the main influencing factors.
This method is based on optical localization of ASA within the sheet structure by confocal white light microscopy. In order to fulfill the requirements at magnification rates of factor 100 optical zoom, it was necessary to improve the contrast between ASA and cellulose. Therefore, ASA was pretreated with an inert red diazo dye, which does not have any impact on neither the sizing nor the handling properties of ASA. Laboratory hand sheets that were sized with dyed ASA, were analyzed by means of their sizing performance in correlation to measurable ASA agglomerations in the sheet structure. The sizing performance was measured by ultrasonic penetration analysis. The agglomeration behavior of ASA was analyzed automatically by multiple random imaging of a sample area of approx. 8650 µm² with a minimum resolution for particles of 500 nm in size. The gained results were interpreted by full factorial design of experiments (DOE). The trials were carried out with ASA dosages between 0% and 0.8% on laboratory hand sheets, made of 80% bleached eucalyptus short fiber kraft pulp and 20% northern bleached softwood kraft pulp, beaten to SR° 30, produced with a RDA sheet former at a base weight of 100 g/m² oven dry.
The results show that there is a defined correlation between the ASA dosage, the sizing performance and the number and area of ASA agglomerates to be found in the sheet structure. It was also possible to show that the agglomeration behavior is highly influenced by external factors like furnish composition and process parameters. This enables a new approach to the explanation of sizing performance, by making it possible to not only examine the performance of the sizing agent, but to closely look at the predominant position where it is located in the sheet structure. These results lead to the explanation that the phenomenon of sizing is by far not a pure chemical process but rather a more physical one. Based on the gained findings it was possible so far to optimize the ASA sizing process in industrial-scale by means of ~ 50% less ASA consumption at a steady degree of sizing and improved physical sheet properties.:Acknowledgment I
Abstract III
Table of Content V
List of Illustrations XI
List of Tables XVI
List of Formulas XVII
List of Abbreviations XVIII
1 Introduction and Problem Description 1
1.1 Initial Situation 1
1.2 Objective 2
2 Theoretical Approach 3
2.1 The Modern Paper & Board Industry on the Example of Germany 3
2.1.1 Raw Materials for the Production of Paper & Board 5
2.2 The Sizing of Paper & Board 8
2.2.1 Introduction to Paper & Board Sizing 8
2.2.2 The Definition of Paper & Board Sizing 10
2.2.3 The Global Markets for Sized Paper & Board Products and Sizing Agents 11
2.2.4 Physical and Chemical Background to the Mechanisms of Surface-Wetting and Penetration 13
2.2.4.1 Surface Wetting 14
2.2.4.2 Liquid Penetration 15
2.2.5 Surface and Internal Sizing 17
2.2.6 Sizing Agents 18
2.2.6.1 Alkenyl Succinic Anhydride (ASA) 19
2.2.6.2 Rosin Sizes 19
2.2.6.3 Alkylketen Dimer (AKD) 23
2.2.6.4 Polymeric Sizing Agents (PSA) 26
2.2.7 Determination of the Sizing Degree (Performance Analysis) 28
2.2.7.1 Cobb Water Absorption 29
2.2.7.2 Contact Angle Measurement 30
2.2.7.3 Penetration Dynamics Analysis 31
2.2.7.4 Further Qualitative Analysis Methods 33
2.2.7.4.1 Ink Stroke 33
2.2.7.4.2 Immersion Test 33
2.2.7.4.3 Floating Test 34
2.2.7.4.4 Hercules Sizing Tester (HST) 34
2.2.8 Sizing Agent Detection (Qualitative Analysis) and Determination of the Sizing Agent Content (Quantitative Analysis) 35
2.2.8.1 Destructive Methods 35
2.2.8.2 Non Destructive Methods 36
2.3 Alkenyl Succinic Anhydride (ASA) 36
2.3.1.1 Chemical Composition and Production of ASA 37
2.3.1.2 Mechanistic Reaction Models 39
2.3.1.3 ASA Application 42
2.3.1.3.1 Emulsification 42
2.3.1.3.2 Dosing 44
2.3.1.4 Mechanistic Steps of ASA Sizing 46
2.3.2 Physico-Chemical Aspects during ASA Sizing 48
2.3.2.1 Reaction Plausibility 48
2.3.2.1.1 Educt-Product Balance / Kinetics 48
2.3.2.1.2 Energetics 51
2.3.2.1.3 Sterics 52
2.3.2.2 Phenomena based on Sizing Agent Mobility 53
2.3.2.2.1 Sizing Agent Orientation 54
2.3.2.2.2 Intra-Molecular Orientation 55
2.3.2.2.3 Sizing Agent Agglomeration 55
2.3.2.2.4 Fugitive Sizing / Sizing Loss / Size Reversion 56
2.3.2.2.5 Sizing Agent Migration 58
2.3.2.2.6 Sizing Reactivation / Sizing Agent Reorientation 59
2.3.3 Causes for Interactions during ASA Sizing 60
2.3.3.1 Process Parameters 61
2.3.3.1.1 Temperature 61
2.3.3.1.2 pH-Value 62
2.3.3.1.3 Water Hardness 63
2.3.3.2 Fiber Types 64
2.3.3.3 Filler Types 65
2.3.3.4 Cationic Additives 66
2.3.3.5 Anionic Additives 67
2.3.3.6 Surface-Active Additives 68
2.4 Limitations of State-of-the-Art ASA-Sizing Analysis 69
2.5 Optical ASA Localization 71
2.5.1 General Background 71
2.5.2 Confocal Microscopy 72
2.5.2.1 Principle 72
2.5.2.2 Features, Advantage and Applicability for Paper-Component Analysis 74
2.5.3 Dying / Staining 75
3 Discussion of Results 77
3.1 Localization of ASA within the Sheet Structure 77
3.1.1 Choice of Dyes 77
3.1.1.1 Dye Type 78
3.1.1.2 Evaluation of Dye/ASA Mixtures 80
3.1.1.2.1 Maximum Soluble Dye Concentration 80
3.1.1.2.2 Thin Layer Chromatography 81
3.1.1.2.3 FTIR-Spectroscopy 82
3.1.1.3 Evaluation of the D-ASA Emulsion 84
3.1.1.4 Paper Chromatography with D-ASA & F-ASA Emulsions 85
3.1.1.5 Evaluation of the D-ASA Emulsion’s Sizing Efficiency 86
3.1.2 The Localization Method 87
3.1.2.1 The Correlation between ASA Distribution and Agglomeration 88
3.1.2.2 Measurement Settings 89
3.1.2.3 Manual Analysis 90
3.1.2.4 Automated Analysis 92
3.1.2.4.1 Automated Localization / Microscopy Measurement 92
3.1.2.4.2 Automated Analysis / Image-Processing 93
3.1.2.5 Result Interpretation and Example Results 96
3.1.2.6 Reproducibility 97
3.1.2.7 Sample Mapping 98
3.1.3 Approaches to Localization-Method Validation 102
3.1.3.1 Raman Spectroscopy 102
3.1.3.2 Confocal Laser Scanning Fluorescent Microscopy 102
3.1.3.3 Decolorization 103
3.2 Factors Impacting the Sizing Behavior of ASA 104
3.2.1 ASA Type 105
3.2.2 Emulsion Parameters 107
3.2.2.1 Hydrolyzed ASA Content 107
3.2.2.2 ASA/Starch Ratio 109
3.2.2.3 Emulsion Age 110
3.2.3 Stock Parameters 111
3.2.3.1 Long Fiber/Short Fiber Ratio 111
3.2.3.2 Furnish Type 112
3.2.3.3 Degree of Refining 114
3.2.3.4 Filler Type/Content 116
3.2.4 Process Parameters 119
3.2.4.1 Temperature 119
3.2.4.2 pH-Value 120
3.2.4.3 Conductivity 122
3.2.4.4 Water Hardness 123
3.2.4.5 Shear Rate 125
3.2.4.6 Dwell Time 127
3.2.4.7 Dosing Position & Dosing Order 128
3.2.4.8 Drying 130
3.2.4.9 Aging 131
3.3 Factors Impacting the Localization Behavior of ASA 132
3.3.1 Degree of Refining 132
3.3.2 Sheet Forming Conductivity 135
3.3.3 Water Hardness 136
3.3.4 Retention Aid (PAM) 137
3.3.5 Contact Curing 138
3.3.6 Accelerated Aging 139
3.4 Main Optimization Approach 141
3.4.1 Optimization of ASA Sizing Performance Characteristics 142
3.4.2 Emulsion Modification 144
3.4.2.1 Lab Trials / RDA Sheet Forming 146
3.4.2.2 TPM Trials 147
3.4.2.3 Industrial-Scale Trials 149
3.4.2.4 Correlation between Sizing Performance Optimization and Agglomeration Behavior on the Example of PAAE 152
3.5 Holistic Approach to Sizing Performance Explanation 154
4 Experimental Approach 157
4.1 Characterization of Methods, Measurements and Chemicals used for the Optical Localization-Analysis of ASA 157
4.1.1 Characterization of used Chemicals 157
4.1.1.1 Preparation of Dyed-ASA Solutions 157
4.1.1.2 Thin Layer Chromatography 157
4.1.1.3 Fourier Transformed Infrared Spectroscopy 157
4.1.1.4 Emulsification of ASA 158
4.1.1.5 Paper Chromatography 159
4.1.1.6 Particle Size Measurement 159
4.1.2 Optical Analysis of ASA Agglomerates 160
4.1.2.1 Microscopy 160
4.1.2.2 Automated Analysis 163
4.1.2.2.1 Adobe Photoshop 163
4.1.2.2.2 Adobe Illustrator 164
4.1.2.3 Confocal Laser Scanning Fluorescent Microscopy 166
4.2 Characterization of Used Standard Methods and Measurements 166
4.2.1 Stock and Paper Properties 166
4.2.1.1 Stock pH, Conductivity and Temperature Measurement 166
4.2.1.2 Dry Content / Consistency Measurement 167
4.2.1.3 Drainability (Schopper-Riegler) Measurement 167
4.2.1.4 Base Weight Measurement 168
4.2.1.5 Ultrasonic Penetration Measurement 168
4.2.1.6 Contact Angle Measurement 169
4.2.1.1 Cobb Measurement 169
4.2.1.2 Air Permeability Measurements 170
4.2.1.3 Tensile Strength Measurements 170
4.2.2 Preparation of Sample Sheets 171
4.2.2.1 Stock Preparation 171
4.2.2.2 Laboratory Refining (Valley Beater) 171
4.2.2.3 RDA Sheet Forming 171
4.2.2.4 Additive Dosing 173
4.2.2.5 Contact Curing 174
4.2.2.6 Hot Air Curing 174
4.2.2.7 Sample Aging 174
4.2.2.8 Preparation of Hydrolyzed ASA 175
4.2.2.9 Trial Paper Machine 175
4.2.2.10 Industrial-Scale Board Machine 177
4.3 Characterization of used Materials 178
4.3.1 Fibers 178
4.3.1.1 Reference Stock System 178
4.3.1.2 OCC Fibers 179
4.3.1.3 DIP Fibers 179
4.3.2 Fillers 180
4.3.3 Chemical Additives 180
4.3.3.1 ASA 180
4.3.3.2 Starches 181
4.3.3.3 Retention Aids 181
4.3.3.4 Poly Aluminum Compounds 181
4.3.3.5 Wet Strength Resin 181
4.3.4 Characterization of used Additives 182
4.3.4.1 Solids Content 182
4.4 Description of Implemented Advanced Data Analysis- and Visualization Methods 183
4.4.1 Design of Experiments (DOE183
4.4.2 Contour Plots 184
4.4.3 Box-Whisker Graphs 185
5 Conclusion 186
6 Outlook for Further Work 191
7 Bibliography 192
Appendix 207
7.1 Localization Method Reproducibility 207
7.2 DOE - Coefficient Lists 208
7.2.1 Trial 3.3.4 – Impact of Retention Aid (PAM) on Agglomeration Behavior and Sizing Performance 208
7.2.2 Trial 3.3.5 – Impact of Contact Curing on Agglomeration Behavior and Sizing Performance 208
7.2.3 Trial 3.3.6 – Impact of Accelerated Aging on Agglomeration Behavior and Sizing Performance 209
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