Sustainable development has become a global goal and the utilization of bioresources is a key way to achieve this crucial goal. Glyoxylic acid-functionalized lignin (GA-lignin) is one of the novel lignin derivatives extracted from beech wood (hardwood) and has great potential to be an industrially important bioresource. In this thesis work, epoxies prepared by GA-lignin and polyethylene glycol diglycidyl ether (PEGDE) were studied, and the feasibility to prepare smart materials based on these epoxies was explored. Three smart properties, including self-healing properties, thermoelectric properties and piezoelectric properties, were successfully embedded in the GA-lignin-based materials. Many applications are envisioned based on the unique properties of GA-lignin and the value-added materials based on this lignin, including adhesives, hydrogels, flexible electronics, etc. In the first part of this thesis work, different pathways were performed to synthesize GA-lignin/PEGDE epoxies: solvent-free pathway, NaOH solution pathway, DMSO solvent pathway and 1,4-dioxane solvent pathway. The elastomeric epoxy with 50wt% lignin was synthesized following the solvent-free pathway showing mild self-healing properties. The introduction of NaOH solution was found to have the ability to enhance self-healing properties. The epoxy obtained following the dioxane solvent pathway had a similar structure to the original one without any medium, therefore dioxane was chosen to be the solvent for further fabrication of nanocomposites. In the second part, two kinds of GA-lignin-based nanocomposites were fabricated with dioxane as solvent. The first kind of nanocomposite was filled with reduced graphene oxide nanoparticles (rGO). 1wt%, 2wt% and 3wt% of rGO nanoparticles were dispersed into the 50wt% GA-lignin/PEGDE epoxy matrix. Power factor analysis was performed, and the potential of GA-lignin-based thermoelectric nanocomposite was verified. The second nanocomposite was filled with barium titanate nanoparticles (BaTiO3). 7.5wt% and 15wt% of BaTiO3 were dispersed into the epoxy matrix and the piezoelectric response test was performed to show the embedded piezoelectric properties. / Hållbar utveckling har blivit ett globalt mål och användningen av bioresurser är ett viktigt sätt att uppnå detta avgörande mål. Glyoxylsyra-funktionaliserad lignin (GA-lignin) är en av de nya ligninderivaten extraherade från bokträ (lövträ) och har stor potential att vara en industriellt viktig bioresurs. I detta examensarbete undersöktes epoxier framställda av GA-lignin och polyetylenglykol-diglycidyleter (PEGDE), och möjligheten att framställa smarta material baserade på dessa epoxier utforskades. Tre "smarta egenskaper" integrerades framgångsrikt i GA-lignin-baserade material, inklusive självläkande egenskaper, termoelektriska egenskaper och piezoelektriska egenskaper. Många tillämpningar förutspås baserat på de unika egenskaperna hos GA-lignin och de mervärdesmaterial som baseras på detta lignin, inklusive lim, hydrogeler, flexibel elektronik, osv.I den första delen av detta examensarbete genomfördes olika metoder för att syntetisera GA-lignin/PEGDE-epoxier: en metoden utan lösningsmedel, en metod med NaOH-lösning, en metod med DMSO-lösningsmedel och en metod med 1,4-dioxan som lösningsmedel. Den elastiska epoxin med 50 viktprocent lignin syntetiserades genom den lösningsmedelsfria metoden och uppvisade milda självläkningsegenskaper. Införandet av NaOH-lösningen visade sig kunna förbättra självläkningsegenskaperna. Epoxin som erhölls genom metoden med dioxan som lösningsmedel hade en liknande struktur som den ursprungliga epoxin utan något medium, därför valdes dioxan som lösningsmedel för vidare tillverkning av nanokompositer. I den andra delen tillverkades två typer av GA-lignin-baserade nanokompositer med dioxan som lösningsmedel. Den första typen av nanokomposit fylldes med reducerade grafenoxid-nanopartiklar (rGO). 1 viktprocent, 2 viktprocent och 3 viktprocent rGO-nanopartiklar disperserades i matrisen av 50 viktprocent GA-lignin/PEGDE-epoxi. En analys av effektfaktorn utfördes och potentialen hos GA-lignin-baserade termoelektriska nanokompositer verifierades. Den andra nanokompositen fylldes med bariumtitanat-nanopartiklar (BaTiO3). 7,5 viktprocent och 15 viktprocent BaTiO3 disperserades i epoximatrixen och en test för piezoelektrisk respons genomfördes för att visa de inbäddade piezoelektriska egenskaperna.

The overall goal of this research was to explore new living radical polymerization methods and the blending of renewable polymers. Towards this latter goal, polylactic acid (PLA) was blended with a new renewable polymer, poly(trimethylene-malonate) (PTM), with the aim of improving mechanical properties, imparting faster degradation, and examining the relationship between degradation and mechanical properties. Blend films of PLA and PTM with various ratios (5, 10, and 20 wt %) were cast from chloroform. Partially miscible blends exhibited Young’s modulus and elongation-to-break values that significantly extend PLA’s usefulness. Atomic force microscopy (AFM) data showed that incorporation of 10 wt% PTM into PLA matrix exhibited a Young’s modulus of 4.61 GPa, which is significantly higher than that of neat PLA (1.69 GPa). The second part of the bioplastics study involved a one-week hydrolytic degradation study of PTM and another new bioplastic, poly(trimethylene itaconate) (PTI) using DI water (pH 5.4) at room temperature, and the effects of degradation on crystallinity and mechanical properties of these films were examined by differential scanning calorimetry (DSC) and AFM. PTI showed an increase in crystallinity with degradation, which was attributed to predominately degradation of free amorphous regions. Depending on the crystallinity, the elastic modulus increased at first, and decreased slightly. Both bulk and surface-tethered stimuli-responsive polymers were studied on amine functionalized magnetite (Fe3O4) nanoparticles. Stimuli-responsive polymers studied, including poly(N-isopropylacrylamide) (PNIPAM), poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), and poly(itaconic acid) (PIA), were grafted via surface-initiated aqueous atom transfer radical polymerization (SI-ATRP). Both Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) spectroscopies showed the progression of the grafting. The change in particle size as a function of temperature was measured using dynamic light scattering (DLS). Once the PIA was grafted from the Fe3O4 nanoparticles for 13 h, the PIA thickness was around 13 nm. After the PNIPAM was grafted for 6 h, the stimuli-responsive nanocomposites with a lower critical solution temperature (LCST) of 32 °C exhibited a particle size of 236 nm. Moreover, a variety of stimuli-responsive bulk block copolymers were synthesized. The stimuli-responsive nanocomposites could be good candidates as drug carriers for the targeted and controllable drug delivery.

This thesis investigates the effect of reaction media on the efficiency of grafting hydrophobic polymers from cellulose nanocrystals (CNCs) via surface-initiated atom transfer radical polymerization (SI-ATRP), with the goal of producing highly-modified CNCs for incorporation into latex-based pressure sensitive adhesives (PSAs). A latex is a dispersion of polymer particles in water made by emulsion polymerization; latexes are commonly used in paints, coatings, elastomers, inks/toners, household products, cosmetics, and adhesives. However, latex-based PSAs often underperform compared to their organic solvent-polymerized counterparts due to a lack of cohesive strength in the cast latex films. The environmental benefit of using latex-based PSAs synthesized in water is significant, but the development of strategies to improve their performance are required. CNCs are hydrophilic rod-shaped nanoparticles with high mechanical strength. Adding CNCs to latex-based PSAs has been shown to improve both adhesive (i.e., tack and peel strength) and cohesive (i.e., shear strength) properties and offers a degree of sustainability because CNCs are derived from natural cellulose sources such as wood pulp. However, their hydrophilicity, particularly relative to the hydrophobic polymers used in PSAs, has constrained CNCs to the continuous (i.e., water) phase of the latex. To improve CNC compatibility with the dispersed (i.e., polymer) phase and improve their distribution in cast latex films, hydrophobic polymers can be grafted from CNCs. However, CNCs with a high polymer graft density are required to ensure their compatibility with monomers/polymers during latex synthesis. To begin, grafting poly(butyl acrylate) (PBA) from CNCs using SI-ATRP in polar dimethylformamide (DMF) versus non-polar toluene was directly compared. The enhanced colloidal stability of initiator-modified CNCs in DMF led to improved accessibility to surface initiator groups during polymer grafting. As such, PBA-grafted CNCs produced in DMF had up to 30 times more grafted polymer chains than PBA-grafted CNCs produced in toluene. The PBA-grafted CNCs produced in DMF showed high contact angles when cast in a film and formed stable suspensions in toluene. This work highlights that optimizing CNC colloidal stability in a given solvent prior to polymer grafting is a more crucial consideration than solvent–polymer compatibility in the context of obtaining high graft densities and thus hydrophobic CNCs via SI-ATRP. The improved polymer grafting method in DMF was then used to produce PBA and poly(methyl methacrylate) (PMMA)-grafted CNCs at two polymer chain lengths. Polymer grafted CNCs were incorporated in situ during a seeded semi-batch emulsion polymerization to produce PBA latex nanocomposite PSAs. Viscosity measurements revealed significant differences between latexes prepared with CNCs versus polymer-grafted CNCs, with the lower viscosities of the latter suggesting their incorporation inside the polymer particles. When CNCs with short polymer grafts were introduced into PSAs at 1 wt. % loading, they exhibited comparable tack and improved peel strength compared to unmodified CNCs (and all properties improved relative to the base latex without any CNCs). This is attributed to their improved distribution throughout the PSA, the enhanced wettability of the substrate with the CNC containing latex, and the increased polymer chain mobility achieved based on the low molecular weight of the grafts. CNCs with long polymer grafts aggregated in the latex and did not improve PSA properties. PMMA-grafted CNCs slightly outperformed PBA-grafted CNCs likely due to the higher glass transition temperature of PMMA. These results provide insight into future optimization of more sustainable latex-based PSA formulations as well as new commercial CNC-latex products, where the presence of low molecular weight grafts on CNC surfaces could improve polymer mobility and tack and peel strength. / Thesis / Master of Applied Science (MASc) / When the adhesives used in tapes, labels or sticky notes are produced using water-based reactions, they normally underperform compared to conventional adhesives produced using toxic solvents. To improve such water-based adhesives, adding nanocellulose (tiny particles derived from wood pulp) during synthesis has been shown to be an asset. Nanocellulose can be chemically modified to improve its compatibility with adhesive ingredients, and thus change the role of nanocellulose during adhesive manufacturing. In this thesis, modified nanocelluloses were added to water-based adhesives to evaluate their effect on performance (i.e., strength and stickiness). It was found that the reaction conditions during nanocellulose modification were crucial for obtaining highly modified particles that are compatible with adhesive ingredients. This work aims to provide insight for future production of less environmentally taxing adhesives made in water and expand the use of nanocellulose in new commercial products.

<p>  </p> <p>Integration of functional thin films on flexible substrates has piqued interests owing to the needs of flexible devices. Selecting a suitable flexible substrate is crucial for such integration. Recently, muscovite mica has been developed as a flexible platform for functional thin film epitaxy growth. Mica can be easily peeled off due to the weak van der Waals interaction between different layers of mica, along with other advantages including cheap, high elasticity and thermal stability, biocompatible, <em>etc</em>. On the other hand, vertically aligned nanocomposites (VANs) have been attractive because of their unique anisotropic structures, which can achieve physical property anisotropy, easy tunability, out-of-plane strain engineering as well as combined multifunctionality. However, limited work on the integration of nanocomposite thin films on mica with tunable physical properties has been reported due to growth challenges. </p> <p>In this dissertation, different ceramic-metal VAN systems integrated on mica substrates towards different functionalities using pulsed laser deposition (PLD) have been demonstrated. The first chapter is on the integration of BaTiO3-Au nanocomposite system on mica. Tunable optical properties have been achieved by controlling the geometries of the Au nanostructures between nanoparticles and nanopillars by varying the growth temperature. The laser energy was also found to play a role in terms of the Au pillar dimension. The second chapter is on the integration of BaZrO3-Co VAN system on mica towards flexible spintronics. Tunable, anisotropic ferromagnetic property has been realized by controlling the aspect ratio of the Co pillars. The third chapter is on integration of BaTiO3-Fe VAN system on mica towards multiferroics. Different buffer layers have been tried out to facilitate the growth of VAN structure. Room temperature ferroelectric and anisotropic ferromagnetic properties of the films have been confirmed. The last chapter is focused on multiphase nitride-metal nanocomposite design and integration, with films showing unique optical and magnetic properties. The reliability and stability of the physical properties of the films have been verified though bending tests. The growth mechanism and criteria of ceramic-metal nanocomposite on mica have also been discussed. These demonstrations all pave a new way towards the integration and design of multifunctional nanocomposites towards flexible nanodevices.</p>

Alkali activated materials are a promising generation of binders, which can be significantly recognized by having lower carbon footprint, being waste originated, and having unique chemistry and thermodynamics. It appears that alkali activated materials can be engineered to exhibit high-tech and intelligent performances with less effort compared to Portland cement-based binders, if appropriately formulated. In addition, alkali activated materials have several inherent properties such as adjustable microstructure and strength, and heat and chemical resistances. Based on these explanations, the focus of this doctoral thesis was on the fabrication and characterization of multifunctional and smart alkali activated nanocomposites. The investigated alkali activated system was composed of fly ash, ground granulated blast-furnace slag (GGBS), and sodium-based silicate and hydroxide. Carbon nanotubes (CNTs) were incorporated into the alkali activated matrix to constitute a functional complex nano system. Multi-walled carbon nanotubes (MWCNTs) were utilized for colloidal, mechanical and microstructural studies and single-walled carbon nanotubes (SWCNTs) applied for electrical, thermoelectric and sensing assessments. The colloidal and mechanical performances and microstructural characteristics have been assessed for the alkali activated nanocomposites, which were fabricated by a dispersion of MWCNTs (0.05 wt.%) into sodium-based silicate and hydroxide solutions and their combination. The highest MWCNTs’ dispersibility and in-solution stability and smallest dimension of agglomerations were observed in the sodium silicate dispersion media. Accordingly, the highest compressive and flexural strengths were accomplished for mentioned nanocomposites, ≈60 MPa & ≈10 MPa, respectively. The reason for the mechanical improvement was the effective reinforcement of MWCNTs when dispersed in sodium silicate. The MWCNTs were more functional in pore refinement and crack propagation control of the nanocomposites’ microstructure. Thermoelectric properties and thermoelectric power generation performances have been studied for the alkali activated nanocomposites and the resultant generator device. SWCNTs were used for the alkali activated thermoelectric generator fabrications. A single piece of nanocomposite with SWCNT content of 1 wt.% could achieve a Seebeck coefficient of ≈16 μV·K-1 and power factor of 0.4 μW·m-1·K-2. The thermoelectric generator device consisted of 10 serially interconnected alkali activated thermoelements (p-type elements). The highest generated thermoelectric voltage and power with inclusion of 1 wt.% of SWCNTs in the nanocomposites were ≈7 mV and ≈0.7 µW, respectively at ΔΤ of 60 K. In the last phase of this doctoral research the idea of ion discrimination and the potential of being a sensor have been conceptualized and demonstrated for SWCNT alkali activated nanocomposites. The alkali activated sensors were produced by incorporation of 0.1 wt.% of SWCNTs based on the results of conducted percolation study. The sensors displayed an ion discrimination potential by transmitting signals with a detectable difference in geometry and magnitude in exposure to the introduced analytes. The discrimination criteria were analytes’ type, concentration, and volumetric quantity. The SWCNT alkali activated sensors showed a higher magnitude of relative resistance in exposure to the sulphuric acid compared to the magnesium sulphate. In addition, the obtained signals in sulphuric acid exposure had a curvature shape but the signals of magnesium sulphate were rectangular. The introduced sensors were applicable for the sulphuric acid concentration detection in a range of 0.001 to 0.1 M. The sensors did not have any upper threshold limit, however the lower threshold limit for sulphuric acid concentration detection was 0.001 M. There was a direct relation between the exposed quantity of sulphuric acid and relative resistance of the alkali activated sensors. The finding of this doctoral research can be utilized for development of alkali activated nanocomposites with industrial implementations. That may include nano reinforced structural elements, thermoelectric generators for green energy production and sensors for structural health monitoring of concrete infrastructures.:Chapter 1. Motivation and innovation 1 1.1. Introduction 1 1.2. Alkali activated materials and geopolymers 1 1.3. Mechanical properties 2 1.3.1. Challenge 2 1.3.2. Novelty 4 1.4. Thermoelectricity 5 1.4.1. Challenge 6 1.4.2. Novelty 6 1.5. Sensing concept 7 1.5.1. Challenge 8 1.5.2. Innovation 10 1.6. Aim 10 1.7. Strength and shortcoming 11 1.8. Structure 11 Chapter 2. Methodology 17 2.1. Materials 17 2.1.1. Carbon nanotubes 17 2.1.2. Surfactants 18 2.1.3. Precursors 19 2.1.4. Activators 20 2.1.5. Analytes 20 2.2. Methods 21 2.2.1. Two-part activation technology 21 2.2.1.1. MWCNTs and naphthalene sulphonate concentrations 21 2.2.1.2. Fabrication methodologies of nanofluids and nanocomposites 21 2.2.1.2.1. Na2Si3.5O9 based nanofluids and nanocomposites (strategy I) 22 2.2.1.2.2. NaOH based nanofluids and nanocomposites (strategy II) 22 2.2.1.2.3. Combined (Na2Si3.5O9+NaOH) nanofluids and nanocomposites (strategy III) 23 2.2.1.3. Dispersion of nanofluids 23 2.2.1.4. Mixing of nanocomposites 24 2.2.2. One-part activation technology 24 2.2.2.1. SWCNTs and SDBS concentrations 25 2.2.2.2. Fabrication methodology of nanofluids 25 2.2.2.2.1. Thermoelectricity 25 2.2.2.2.2. Sulphate sensing 25 2.2.2.2.3. Sulphuric acid sensing 25 2.2.2.3. Fabrication methodology of nanocomposites 26 2.2.2.3.1. Thermoelectricity 26 2.2.2.3.2. Sulphate sensing 26 2.2.2.3.3. Sulphuric acid sensing 26 2.3. Characterizations 27 2.3.1. Optical microscopy 27 2.3.2. Integral light transmission (ILT) 27 2.3.3. Scanning electron microscopy (SEM) 27 2.3.4. Transmission electron microscopy (TEM) 28 2.3.5. Fourier-transform infrared spectroscopy (FTIR) 28 2.3.5.1. Alkaline nanofluids 28 2.3.5.2. Chemiresistor nanocomposites 29 2.3.6. Mercury intrusion porosimetry (MIP) 29 2.3.7. Roughness measurements 29 2.3.8. pH measurements 29 2.3.9. Mechanical properties 29 2.3.10. Thermoelectric acquisitions 30 2.3.11. Thermoelectric generator acquisitions 31 2.3.12. Sensing and discriminating acquisitions 31 Chapter 3. Dispersion of CNTs 33 3.1. Introduction 33 3.2. MWCNTs dispersibility 33 3.3. MWCNTs dispersion stability 36 3.4. MWCNTs and naphthalene sulphonate interactions 38 3.5. Potential physisorption 42 3.6. Conclusion 44 3.7. Perspective 44 Chapter 4. Microstructure refinement 45 4.1. Introduction 45 4.2. Mechanical reinforcement 45 4.3. Reinforcement mechanism 49 4.3.1. Morphology 49 4.3.2. Porosity 55 4.4. Conclusion 60 4.5. Perspective 61 Chapter 5. Thermoelectricity 63 5.1. Introduction 63 5.2. Thermoelectric properties 63 5.3. Thermoelectric generator 65 5.3.1. Power output 65 5.3.2. Stability performance 69 5.4. Mechanical properties 70 5.5. Multifunctional behaviour 71 5.6. Conclusion 73 5.7. Perspective 74 Chapter 6. Sulphate discrimination 77 6.1. Introduction 77 6.2. Percolation threshold 77 6.3. Sulphate discrimination 80 6.4. Concentration differentiation 84 6.5. Quantity differentiation 86 6.6. Conclusion 88 6.7. Perspective 89 Chapter 7. Sulphuric acid sensing 91 7.1. Introduction 91 7.2. Electrical properties 91 7.3. Morphology of the SWCNTs’ conductive network 92 7.4. Sensing properties 96 7.4.1. Exposure to ultrapure water 96 7.4.2. Exposure to sulphuric acid 97 7.4.2.1. pH influence 100 7.4.2.2. Surface composition change 103 7.4.3. Sensor sensitivity 106 7.5. Microstructure dependency 109 7.5.1. SWCNTs and matrix interactions 109 7.5.2. Matrix porosity 113 7.5.3. Matrix roughness 115 7.6. Conclusion 118 7.7. Perspective 119 Summary 121 References 123 Publications from this doctoral research 151

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24647号 / 工博第5153号 / 新制||工||1984(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 大嶋 正裕, 教授 佐野 紀彰, 教授 山本 量一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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