Nature creates high performance materials under modest conditions, i.e., neutral pH and ambient temperature and pressure. One of the most significant materials is the plant cell wall. The plant cell wall is a composite of oriented cellulose microfibrils reinforcing a lignin/hemicellulose matrix. In principle, the plant cell wall composite is designed much like a synthetic fiber-reinforced polymer composite. Unlike synthetic composites, the plant cell wall has an excellent combination of high modulus, strength, toughness and low density that originates in the optimal interactions between the biopolymers. Therefore, to produce high performance composites, a unique route may be to mimic a biological system like the plant cell wall. The present work focuses on understanding the thermodynamics of biopolymer assembly to exploit the process in vitro. In our system, we use an already polymerized nanocellulose template and polymerize phenolic monomers on the template using a peroxidase enzyme. In the first part, we have polymerized phenol using horseradish peroxidase (HRP) in the presence of TEMPO-oxidized nanocellulose. Similar to native plant cell wall structures, the polyphenol-nanocellulose composite had intimate mixing of polyphenol and cellulose at the nanoscale with the presence of cellulose promoting a uniquely organized structure. The obtained composite material showed synergy that enhanced the thermal stability, hydrophobicity, and possibly mechanical properties. In the second part, monolignol coniferyl alcohol was polymerized in the presence of nanocellulose by the same procedure. A comparison between the polyphenol composite and poly(coniferyl alcohol) (PCA) composite revealed that the propanyl substitution imparted flexibility to the PCA molecules so that they could bend and form a hollow globule structure to envelope nanocellulose inside. Polyphenol could not do this because of its rigidity. / Master of Science

An unprecedented comprehensive study of ammonium and phosphonium polyelectrolytes probed and examined structure-property relationships with a focus on different macromolecular properties. Conventional free radical polymerization readily generated a large library of ammonium- and phosphonium-containing polyelectrolytes. Along with the two different cationic atoms, the alkyl substituent lengths and counterions were varied to generate a thorough structure-property relationship analysis. Phosphonium macromolecules displayed improved thermal stabilities and improved ionic conductivities compared to ammonium analogs. Longer alkyl substituent lengths systematically decreased the glass transition temperatures of all polyelectrolytes; the larger, bulkier counterions also resulted in lower glass transition temperatures. Counterion also impacted the thermal stability of the polymerized ionic liquids with less basic counterions leading to improved thermal stability. For the first time, the efficacy of phosphonium macromolecules for nonviral nucleic acid delivery was examined. Phosphonium macromolecules more efficiently complexed nucleic acids than ammonium analogs and butyl-containing phosphonium macromolecules delivered nucleic acids more effectively than the ammonium analog. Controlled radical polymerization generated unprecedented phosphonium-containing diblock copolymers and these diblock copolymers displayed enhanced colloidal stability and lower cytotoxicity compared to the phosphonium homopolymer for nucleic acid delivery. Step-growth polymerization techniques enabled the synthesis of well-defined, high molecular weight phosphonium ionenes for the first time. Phosphonium ionenes exhibited higher thermal stability and alkaline stability compared to ammonium ionenes. Due to their high thermal stability and relatively low glass transition temperatures, unprecedented melt rheology studies on polyelectrolytes probed the melt flow characteristics of phosphonium ionenes. Novel phosphonium gemini surfactants displayed interesting solution properties in aqueous and chloroform solutions. Electrospinning of the phosphonium gemini surfactants created uniform fibers. The synthesis and characterization of sulfonium polyelectrolytes enabled the first examination of sulfonium macromolecules for nonviral nucleic acid delivery. Sulfonium polyelectrolytes successfully bound nucleic acids and delivered them in vitro. Controlled radical polymerization generated innovative AB diblock and ABA triblock copolymers that displayed salt- and temperature-responsive properties suitable for biological applications such as drug delivery vehicles and hydrogels. Finally, adenine-containing polyelectrolytes were synthesized and they were successfully electrospun to generate adenine-decorated nanofibers appropriate for filtration and nonwoven applications. / Ph. D.

Novel A-A and A-B difunctional monomers were synthesized by utilizing Reissert compound chemistry and via the use of bis(α-aminonitrile)s. These monomers were produced in high yields with preformed heterocyclic nuclei which included benzothiazole, isoquinoline and quinoline. Acylated linear polyamine derivatives were obtained by the step growth condensation polymerization of open chain bis(Reissert compound)s with suitable dihaloalkanes; intrinsic viscosities of up to 0.48 dl/g were obtained in unoptimized runs. The constitutional repeat unit of these polymers consists of four independent structural variables and thus provides versatility for tailor made macromolecular syntheses. Novel bis(Schiff base) monomers based on 1,4-trans-diamino cyclohexane were synthesized and these could be used either directly in the production of poly(azomethine aryl ether)s or synthesis of diamines and dicarboxylic acids containing the trans cyclohexyl moiety. Novel aromatic diamine based bis(α-aminonitrile)s were synthesized from commercially available diamines and are currently being used in the syntheses of post-reaction modifiable co-polyamides. A novel and unique product of rearrangement of benzothiazole Reissert compounds was isolated and characterized. It was postulated that the reaction proceeds via a bimolecular reaction between 2-cyanobenzothiazole and the’ ring opened azomethinethiophenoxide followed by an intramolecular acyl transfer and eventual reaction with methyl iodide leading to a novel benzothiazine. A novel nucleophilic aromatic substitution reaction was discovered which involved the reaction of a masked carbonyl carbanion synthon with activated aromatic fluorides. Hitherto unknown poly(aryl ketone sulfone)s were synthesized when this chemistry was extended with the use of bis(α-aryl aminonitrile)s. A novel quinodimethane was synthesized in quantitative yield by an intramolecular dehydrocyanation. Its structural features are unique in that one end is substituted by a donor moiety while the other end is captodative: this makes it attractive in the fields where electrical conductance and non linear optical (NLO) applications are important. / Ph. D.

This work focused on the formation and the subsequent use of a difunctional organolithium as an anionic polymerization initiator for primarily diene monomers. The initiator was formed in nonpolar solvent such as cyclohexane and toluene by the addition of two equivalents of sec-butyllithium to one of the nonconjugated diene 1,3-bis(α-phenylethenyl)benzene. The disappearance of the starting diene was easily followed by UV/Visible spectroscopy. Rate expressions were evaluated based on the assumptions of a consecutive reaction mechanism and association behavior of the alkyl lithium. Arrhenius behavior was observed and an activation energy of 19 Kcal/mole was determined. Unlike the spectroscopic techniques, gas chromatography was able to separate the unreacted diene, mono-, and diaddition products but dramatic increases in sensitivity were realized by using a capillary column techniques, thus allowing the direct analysis of initiator solutions that were routinely used for high molecular weight polymerizations. Quantitative determination of all reaction components confirmed the existence of a consecutive reaction mechanism for this addition and the data strongly suggested that the second rate constant was an order of magnitude faster than the first in cyclohexane. Using the chromatographic technique to monitor initiator formation, the dianionic diaddition product was maximized by the simple addition of more sec-butyllithium. Polydiene homopolymers were then routinely prepared with predictable molecular weights and narrow polydispersities. Successive addition of isoprene and styrene resulted in triblock copolymers that incorporated both monomers over a wide compositional range. Novel triblock systems that contained t-butyl methacrylate end blocks and an isoprene center block were prepared by addition of THF which facilitated the efficient crossover. A new trialkyl sodium magnesiate initiator was evaluated as an alternative to alkyllithiums for the polymerization of vinyl and cyclic monomers. Homopolymerizations of isoprene and styrene showed slow initiation rates and uncontrollable molecular weights relative to sec butyllithium. This initiator also polymerized methyl methacrylate in high yields without modification of its basicity and steric bulk. / Ph. D.

Novel functionalized triphenylphosphine oxide containing monomeric materials were prepared and subsequently incorporated into high performance aromatic polyimides, polyamides, copolysiloxane-poly(aryl-imide) randomly segmented copolymers, and epoxy network systems. These uniquely designed monomers were prepared via both Friedel-Crafts and Grignard techniques. In particular, two arylene ether diamines, bis[4-(maminophenoxy)phenyl]phenylphosphine oxide (m-BAPPO) and bis[4-(paminophenoxy)pheny] |phenylphosphine oxide (p-BAPPO) were prepared via the nucleophilic aromatic substitution of aminophenoxides onto the activated dihalide bis(4- fluorophenyl)phenylphosphine oxide (BFPPO) in polar aprotic solvents. It was also shown that the reaction of phenylphosphonothioic dichloride with biphenyl or diphenyl ether in the presence of aluminum chloride is a viable method for preparing regiospecific triphenylphosphine oxide derivatives. These derivatives were oxidized, nitrated and reduced to afford isomeric triphenylphosphine oxide containing diamines. Moreover, a sequential addition procedure with thiophosphoryl chloride, fluorobenzene, and benzene with aluminum chloride was investigated for the preparation of the highly desired, activated dihalide BFPPO. The polymers prepared from the novel triphenylphosphine oxide diamines showed many unique features. All linear polymers displayed high glass transition temperatures (T_g) and substantial improvements in solubility. TGA analyses showed excellent thermooxidative stability for all prepared polymers and gave substantial amounts of char at temperatures where other engineering polymers were completely volatized. This char was shown to induce a self extinguishing behavior in the polymers, thus imparting flame retardancy into the polymeric systems. / Ph. D.

Atom transfer radical polymerization (ATRP) is one of the most commonly employed techniques for controlled radical polymerization. ATRP has great potential for the development of new materials due to the ability to control molecular weight and polymer architecture. To fully utilize the potential of ATRP as polymerization technique, the mechanism and the dynamics of the ATRP equilibrium must be well understood. In this thesis, various aspects of the ATRP process are explored through both laboratory experiments and computer modeling. Solvent effects, the limit of control and the use of iron as the mediator have been investigated. It was shown for copper mediated ATRP that the redox properties of the mediator and the polymerization properties were significantly affected by the solvent. As expected, the apparent rate constant (kpapp) increased with increasing activity of the mediator, but an upper limit was reached, where after kpapp was practically independent of the mediator potential. The degree of control deteriorated as the limit was approached. In the simulations, which were based on the thermodynamic properties of the ATRP equilibrium, the same trend of increasing kpapp with increasing mediator activity was seen and a maximum was also reached. The simulation results could be used to describe the limit of control. The maximum equilibrium constant for controlled ATRP was correlated to the propagation rate constant, which enables the design of controlled ATRP systems. Using iron compounds instead of copper compounds as mediators in ATRP is attractive from environmental aspects. Two systems with iron were investigated. Firstly, iron/EDTA was investigated as mediator as its redox properties are within a suitable range for controlled ATRP. The polymerization of styrene was heterogeneous, where the rate limiting step is the adsorption of the dormant species to the mediator surface. The polymerizations were not controlled and it is possible that they had some cationic character. In the second iron system, the intention was to investigate how different ligands affect the properties of an ATRP system with iron. Due to competitive coordination of the solvent, DMF, the redox and polymeri­zation properties were not significantly affected by the ligands. The differences between normal and reverse ATRP of MMA, such as the degree of control, were the result of different FeIII speciation in the two systems. / QC 20110406

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20403号 / 工博第4340号 / 新制||工||1673(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 澤本 光男, 教授 中條 善樹, 教授 赤木 和夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24814号 / 工博第5157号 / 新制||工||1985(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 山子 茂, 教授 辻井 敬亘, 教授 大内 誠 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

1,8-bis(phenylimino)-3,6-ditertbutyl-carbazole is synthesized and characterized, which can be complexed with copper(II) halide by deprotonation and transmetallation. The resulting copper complexes enable to polymerize MMA through RATRP process.