Textiles made from natural sources, such as cotton and flax, have advantages over those made of synthetic fibers in terms of sustainability. Unlike major synthetic fibers that have a negative impact on the environment due to poor biodegradability, cotton cellulose is a renewable material.Cotton cellulose fibers exhibit various attractive characteristics such as softness and inexpensiveness. Cellulosic textiles can be easily wetted, since the structure contains a large amount of hydrophilic hydroxyl groups, and when water repellency is needed, this is a disadvantage. Currently, paraffin waxes or fluorinated silanes are used to achieve hydrophobicity, but this contradicts the concept of green chemistry since these chemicals are not biodegradable. The use of bio-based materials like forest residues or side-streams from forest product industries might be a good alternative, since this not only decreases the pressure on the environment but can also increase the value of these renewable resources.Betulin is a hydrophobic extractive present in the outer bark of birch trees (Betula verrucosa). Nowadays, the birch bark containing betulin generated in the paper industry is disposed of by incineration as a solid fuel to provide energy, but this application is not highly valuable and this motivates us to see whether betulin can be used as a hydrophobe to prepare waterproof cellulosic textiles. Methods of dip-coating, film compression molding and grafting were performed to build “betulin-cellulosic textile system” to render the textile with hydrophobicity and other functions. The textile impregnated in a solution of betulin-based copolymer exhibited a contact angle of 151°, which indicated that superhydrophobicity can be reached. AATCC water spray test results showed that cellulosic textile coated with betulin-based film had a water repellency of 80, which is the third highest class according to the rating standards. Betulin-grafted textiles were also prepared and showed a static water contact angle of 136°, and an antibacterial property with a bacterial removal of 99%.This thesis proposes that betulin can be used as a green alternative in functional material preparation. By developing betulin, a more value-added application rather than incineration can be achieved. / <p>QC 20190205</p>

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.

Globalization and centralization have resulted in prolonged transportation time between producer and consumer, and thus put more demand on the perseveration of a product for longer duration and protect it from oxidation. The presence of oxygen in packages severely foreshortens the storage life as it yield losses of nutrients and allow microbial growth, which can cause changes in smell, taste as well as discoloration. Earlier food and beverage containers were made in inorganic materials e.g. metal and glass, however lately more and more focus have been on synthetic organic materials as these show several advantages, e.g. weight. However, still today most of the commercial packaging materials, organic or inorganic, are not considered to be environmental friendly. Thus, efforts have to be made today in order to invent alternative materials that can make the society of tomorrow more sustainable. Cellulose is the most abundant biopolymer in the world, hence making it desirable to use in “green” packaging applications. Furthermore, cellulose has proven being able to form films with great gas barrier potential under specific conditions. However, cellulose based materials are sensitive to moisture with severely increased oxygen transmission with increased relative humidity as a result; hence it is desired to make cellulose less hygroscopic by chemical modification. First, nanofibrillated cellulose (NFC) with 720 mmol carboxylic groups/g fiber was produced by oxidation of dissolving pulp before homogenization. Thereafter a polymer was synthesized utilizing Initiator A as an initiator at T1 and T2. The polymer synthesized at T1 yielded a polymer with a viscosity average molecular weight of 5770 g/mol.  The polymer was then grafted on the oxidized NFC through a coupling reaction performed in Buffer C using Coupling agent A. The grafting procedure was performed in Buffer C at ambient conditions giving rise to a material composed of 33 wt% synthetic polymer and 67 wt% NFC. The coupling was conducted several times in order to investigate how the final product can be affected by varying reactant feed and dispersion method. Finally, films of NFC and NFC-g-Polymer were manufactured by vacuum filtration from a 0.05 wt% Solvent A dispersion and were evaluated with field emission scanning electron microscopy.

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The potential impact of carbon dioxide as a major source of global warming has led to extensive research in order to mitigate the greenhouse effect. In this work, four adsorbents were synthesized and studied. The adsorbents were obtained by grafting and sol-gel of amino-containing molecules such as bis[3-(trimethoxysilyl)propyl]amine as monoamine and [3-(2-aminoethylamino)propyl]- trimethoxysilane as diamine on the surface of silica gel. CO2 passed through adsorbents at room temperature for its capture, then desorbed at moderate heating, and stored in the form of insoluble BaCO3. The adsorbent synthesized by sol-gel synthesis was found to be more efficient due to its high content of amino groups. A demonstration experiment on reversible adsorption of CO2 on mesoporous modified silica gel was developed. This experiment visualizes a technology of post-combustion CO2 sequestration from industrial emission gases and its storage.

BACKGROUND: The ultrasonic vibrations from the piezoelectric knife may amplify the natural response to surgical injury. This may lead to different clinical and biological outcomes when using the piezoelectric knife versus a surgical bur to create selective cortical penetrations for alveolar ridge augmentation surgeries. The first aim of this study was to analyze the differences in bone graft healing when selective cortical penetrations are created with a surgical bur and with a piezoelectric knife. The second aim of this pilot study was to see if enhanced new bone formation during bone regeneration procedures can be achieved with the use of a piezoelectric knife versus the conventional bur or onlay grafting techniques utilizing deep learning, a subset of machine learning. MATERIALS & METHODS: he project was approved by the Boston University Medical Center Institutional Animal Care and Use Committee (IACUC). Twenty, 9-10 week male Sprague Dawley rats, weighing approximately 300g, were used in this study. The rats were randomly divided into three groups: Xenograft, Alloplast, and Collagen. These groups were further divided by surgical technique: Bur, Piezo, and Onlay. For the Bur and Piezo groups, four equally-spaced selective cortical penetrations were made prior to bone graft stabilization. Three rats served as controls (Control group). Microcomputed tomography scans (µCT) were acquired for each sample, containing approximately 1,000 slices of data each. After 28 days of healing the volumes of and density of the newly formed bone were extracted and analyzed for each group. This was achieved with an innovative deep learning algorithm designed for multi-level segmentation and regional feature detection utilizing convolutional neural networks (CNN). RESULTS: Microcomputed tomography (µCT) of our samples yielded very localized, high-resolution scans of our surgical samples. The innovative deep learning algorithm was able to reliably produce highly accurate, unbiased segmentations of our samples. This study demonstrated that new bone formation was possible with all nine of the tested surgical techniques, however the differences were not statistically significant. Selective cortical penetrations with a piezoelectric knife (PIEZO) resulted in significantly more “cortical-like” new bone formation at 28 days. CONCLUSION: Within the limitations of this preliminary study, it is possible to conclude that the piezoelectric knife is a valid alternative to conventional carbide burs when making selective cortical penetrations prior to bone grafting surgery. Additionally, our deep learning algorithm successfully segmented thousands of slices of data and allowed for the calculation of porosity and new bone volume in our samples.

The research presented in this dissertation focuses on the design and synthesis of novel hybrid conjugated polymer materials using two different approaches: 1) inorganic/organic hybrid semiconductors through the incorporation of carboranes into the polymer structure and 2) the modification of surfaces with conjugated polymers via grafting approaches. Hybrid conjugated polymeric materials, which are materials or systems in which conjugated polymers are chemically integrated with non-traditional structures or surfaces, have the potential to harness useful properties from both components of the material to help overcome hurdles in their practical realization in polymer-based devices. This work is centered around the synthetic challenges of creating new hybrid conjugated systems and their potential for advancing the field of polymer-based electronics through both greater understanding of the behavior of hybrid systems, and access to improved performance and new applications. Chapter 1 highlights the potential applications and advantages for these hybrid systems, and provides some historical perspective, along with relevant background materials, to illustrate the rationale behind this work. >Chapter 2 explores the synthesis of poly(fluorene)s with pendant carborane cages. The Ni(0) dehalogenative polymerization of a dibromofluorene with pendant carborane cages tethered to the bridging 9-position produced hybrid polymers produced polymers which combined the useful emissive characteristics of poly(fluorene) with the thermal and chemical stability of carborane cages. The materials were found to display increased glass transition temperatures and showed improved emission color stability after annealing at high temperatures relative to the non-hybrid polymer. The design and synthesis of a poly(fluorene)-based hybrid material with carborane cages in the backbone, rather than as pendant groups, begins in chapter 3. Poly(fluorene) with p-carborane in the backbone is synthesized and characterized, and the material is found to be a high MW, soluble blue emitter which shows a higher glass transition temperature and greater stability than a non-hybrid polymer. UV absorbance and fluorescence spectroscopy indicated some electronic interaction between the conjugated polymer and the cages, but they did not appear to be fully conjugated in the traditional sense. Chapter 4 describes the design, synthesis, and characterization of poly(fluorene) with o-carborane in the backbone. Profound changes in the behavior of the polymer, from its polymerization behavior to its emission characteristics, were observed and their origins are discussed. Experiments to explore the nature of the cage/polymer interactions were performed and possible applications which take advantage of the unique nature of the o-carborane hybrid polymer are explored and discussed. Hybrid conjugated polymer materials via grafting approaches to surfaces and surface modification are discussed starting in chapter 5. The synthesis of a dibromofluorene-based silane coupling agent for the surface functionalization of oxide surfaces is presented, and the surface directed Ni(0) dehalogenative polymerization of poly(dihexylfluorene) is explored. Chapter 6 focuses on the exploration of conjugated polymer/cellulose hybrid materials. Surface medication of cellulose materials with monomer-like anchor points is discussed. Grafting of the modified cellulose with conjugated polymers was explored and the grafting of three different repeat structures based on fluorene-, fluorenevinylene-, and fluoreneethynylene motifs were optimized to provide a general route to cellulose/conjugated polymer hybrid materials. Characterization and possible applications of such hybrid materials are discussed. Finally, chapter 7 is devoted to the simultaneous surface patterning and functionalization of poly(2-hydroxyethylmethacrylate) thin films using a silane infusion-based wrinkling technique. While not a conjugated polymer system, the spontaneous patterning and functionalization methods explored in this chapter produce hybrid organic/inorganic polymer thin films which have applications that range from optics, to adhesion, to polymer-based electronics, and the research compliments the other chapters. The spontaneous generation of complex patterns, of a small scale approaching 100nm feature size, over a large area with simultaneous control over surface chemistry is explored. Examples of complex, hierarchically patterned films which integrate lithographic processes such as nanoimprint lithography and electron beam lithography with spontaneous patterning via wrinkling are presented.

Sustainable practices were evaluated for the production of two warm season vegetable crops, tomato and chile peppers. The first study investigated the plant vegetative growth, fruit production timing, yield components and fruit quality of three hybrid and three heirloom tomato cultivars grown in a high tunnel using grafted and non-grafted plants. Grafting the selected tomato cultivars with the two rootstock types did not alter total marketable yield of any cultivar, but affected overall stem diameter, fruit color, and β-carotene concentrations of tested tomato cultivars. The second study evaluated the plant growth, yield, and fruit quality of nine heirloom chile pepper cultivars treated with three types of biostimulants during 2020 and 2021. Biostimulant application did not affect marketable yield in 2020 or 2021, but enhanced fruit quality including fruit length, diameter, and green coloration.

京都大学 / 新制・論文博士 / 博士(農学) / 乙第13498号 / 論農博第2902号 / 新制||農||1093(附属図書館) / 学位論文||R4||N5404(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 中﨑 鉄也, 教授 土井 元章, 教授 田尾 龍太郎 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM