The University of Arizona has developed an advanced extruder-feeder biomass liquefaction reactor system. This 11-year project successfully provided an alternative energy process for converting biomass to a crude oil, which can be hydrotreated and ultimately processed into liquid transportation fuels. In order to provide support studies for this process, a short-residence time autoclave capable of providing very brief heat-up and quenching periods in comparison to the time at reaction temperature has been designed and operated. Wood liquefaction in the presence of carbon monoxide, water, and sodium carbonate catalyst has been conducted at residence times of 1.75-60 minutes at temperatures of 340-400°C. Results indicate that the primary thermal decomposition reactions reach completion in less than 1.75 minutes. As a consequence, this research concentrated mostly on the effects of secondary reactions, and even shorter residence times are required to study the primary reactions.

Theoretical calculations have predicted the importance of two-photon absorptions in the third order optical nonlinearities of polydiacetylenes. We have used electro-absorption techniques to make these two-photon transitions slightly one-photon allowed and therefore observable in the one-photon absorption spectrum. Our findings, although unable to ascertain the existence of below-gap two-photon states, nevertheless provide an unexpected view of the conduction band in conjugated chain polymers. The observation of a field induced oscillatory change in the absorption around the vicinity of the band edge and comparison of this signal with theoretical calculations leads to the conclusion that the conduction band is composed of both one-photon and two-photon states. This oscillatory signal cannot be solely explained by one-photon or two-photon states but must include both types for this high energy signal to be reproduced in the theoretical calculations.

This dissertation summarizes the investigation of interfacial phenomena using novel in situ techniques. The Quartz Crystal Microbalance (QCM) was employed to monitor polymer adsorption from solution onto gold surfaces. Kinetics, isotherms, and competition in polymer adsorption were studied. Adsorption kinetics for polymers of narrow or wide molecular weight distribution were observed. Adsorption of copolymers with thiol functional groups onto gold surfaces was monitored. Adsorption models were constructed assuming the formation of a uniform single-polymer chain layer on the gold surface. / Surface-enhanced Raman scattering (SERS) was measured for strongly chemisorbed compounds and water soluble polymers on colloidal gold in the mixed solvents using an 826 nm diode laser or on silver hydrosol with a 514.5 nm argon ion laser. The colloidal solution of gold was more stable in the mixed solvents of water and ethanol than in aqueous solvent alone. Strong SERS was generated with near-IR excitation on gold colloids for mercaptopyridine and thiophenol. The estimated enhancement is on the order of 10$\sp5.$ The enhancement kinetics and concentration correlation for mercaptopyridine on gold colloids were studied in order to obtain quantitative analysis. New adsorbates, such as 2-mercaptoethanesulfonate and ethanesulfonate sodium for SERS were examined with an argon ion laser on silver hydrosol. The effect of chemisorption and physisorption was compared. Strong SERS of poly(vinyl benzyl trimethylammonium chloride), and its monomer were measured on silver hydrosol. It was demonstrated that strong colloidal aggregation is not essential for generating SERS in a colloidal system. Transmission electron microscopy (TEM) was used to monitor the colloidal particle morphology changes during aggregation. / Modifications of conducting polymers were performed by extended oxidation on electrodes. The electrochemical behavior of conducting polymers was studied systematically by cyclic voltammetry. Well-defined, stable redox behavior was obtained. Temperature is found to play an important role in the overoxidation of conducting polymers. Water and oxygen also have significant effects on these processes. The conductance and destruction of polypyrrole film were examined at various applied potentials and temperatures. Compositional changes of polypyrrole during extended oxidation were detected by FTIR. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1412. / Major Professor: Joseph B. Schlenoff. / Thesis (Ph.D.)--The Florida State University, 1994.

Comprehending DNA organization in vivo requires an understanding of how DNA self organizes to form liquid crystalline phases in highly concentrated solutions. Semi-rigid polymers such as DNA begin to form liquid crystalline phases above a critical concentration (C$\sb{\rm i}$), and are fully liquid crystalline above another critical concentration (C$\sb{\rm a}$). These critical concentrations decrease with increasing polymer length to a limit determined by the persistence length (P). Stiff chains (high P), form ordered phases more readily than flexible chains (low P). The critical concentrations for DNA solutions in buffered NaCl were determined using $\sp{31}$P solid state NMR methods for DNA fractions of selected lengths, ranging from $\approx$50 nm to 2700 nm. Anisotropy was confirmed by polarized light microscopy. / The observed decrease in critical concentration (C$\sb{\rm i}$) (for appearance of ordered phase) with increasing DNA length was more pronounced than predicted by theory, assuming a consensus persistence length of 50 nm for double stranded DNA. The anisotropic phase for very long DNA (2700 nm or 8000 bp) exists beyond a concentration of $\approx$13 mg/ml, well within the physiological range. By contrast, the length dependencies of C$\sb{\rm a}$ is in reasonable accord with expectations based on a 50 nm persistence length. Since the dominant length scale for phase transitions of semiflexible polymers is the persistence length and not the contour length, the unexpectedly broad biphasic region observed for DNA is consistent with recent indications of sequence-dependent variations in DNA flexibility. / Source: Dissertation Abstracts International, Volume: 55-01, Section: B, page: 0060. / Major Professor: Randolph L. Rill. / Thesis (Ph.D.)--The Florida State University, 1993.

The crystallization behavior in the extremes of crystallization of pure polymer and from dilute solution have been extensively studied. However, studies over the intervening concentration range are very sparse. Therefore, studies have been carried out toward the structural properties, morphology and crystallization kinetics of polyethylene crystallized from solution, over a wide concentration range (from dilute to pure polymer), and a wide range of molecular weights (from low to very high molecular weight) using many analytical techniques. / By the use of Raman spectroscopy, the phase structure of the three major regions of crystalline polymer, i.e., the ordered crystalline region, the disordered liquid-like interlamellar region, and the interfacial region, has been examined. The major parameters obtained are the thicknesses and mass fractions of the three regions. The mass fraction of ordered crystalline region showed a sharp increase in the range of 10-20% polymer concentration, and the mass fraction of interfacial region showed a sharp drop at a similar concentration. It is shown that chain entanglements play a very important role in determining the final structure crystallized from solution. The entanglement effect on the interfacial structure is very significant. When entanglements are trapped in the interphase, the amount of tight adjacent chain folds is reduced, and the interfacial thickness and the interfacial free energy increase. Studies of crystallization kinetics, over the large composition and molecular weight range also reveal the influence of entanglements and a correlation with resulting properties. The crystallization behavior in concentrated solution differs from that in dilute solution because of the entanglement effect. The supermolecular structure developed are very sensitive to the polymer concentration and molecular weight. Significant changes take place in the morphological map with dilution. Very high molecular weights, which form randomly oriented lamellar structure in the melt, can develop spherulitic structure in solution. Under particular conditions of composition, molecular weight and temperature very large polyethylene spherulites develop. / Source: Dissertation Abstracts International, Volume: 53-09, Section: B, page: 4697. / Major Professor: Leo Mandelkern. / Thesis (Ph.D.)--The Florida State University, 1992.

Raman spectroscopy performs direct analysis and therefore is non-destructive to paint and needs few sample pretreatments. In the first phase of the work, paint components, including polymeric binders, pigments and other additives, were characterized individually in order to give reference Raman spectra. This provided the basis for their identification when the dry paint films are measured. For chemical analysis of dry opaque paint films, Raman spectroscopy is breaking a new ground. Good Raman spectra were obtained from both solvent- and water-borne paints. / Based on the above successful measurements, the fiber-optic Raman spectroscopy was used for paint degradation studies. The corrosion of a two-part polyurethane paint caused by organic liquids was observed through the Raman spectra. The weathering effect on a water-borne vinyl acrylic latex paint was monitored quantitatively. Both chemical corrosion and weathering processes were measured in real time without disturbing the samples. / Raman spectroscopy has unique advantages in many aspects of paint analysis. It is a robust tool in monitoring the paint curing process and is helpful in new product development. / Source: Dissertation Abstracts International, Volume: 56-08, Section: B, page: 4289. / Major Professor: Chalres K. Mann. / Thesis (Ph.D.)--The Florida State University, 1995.

Novel porphyrin molecules having active peripheral groups, namely 5,10,15,20-tetrakis($\alpha$-bromo-p-tolyl)porphyrin (pTBTP), 5,10,15,20-tetrakis($\omega$-bromo-p-hexoxylphenyl)porphyrin (pTBHP), 5,10,15,20-tetrakis($\alpha$-mercapto-p-tolyl)porphyrin (pTMTP), 5,10,15,20-tetrakis($\omega$-mercapto-p-hexoxylphenyl)porphyrin (pTMHP) and 5,10,15,20-tetrakis($\alpha$-mercapto-m-tolyl)porphyrin (mTMTP), have been synthesized and characterized. Metallation of these porphyrins was also studied, only mTMTP among the three mercaptoporphyrins can be metallated (Cu(II) and Co(II)) directly. Chemisorption of the three mercaptoporphyrins and Co(II)mTMTP has been investigated. Porphyrin self-assembled monolayer(SAM)-modified gold electrodes were prepared and characterized with x-ray photoelectron spectroscopy, reflectance spectroscopy, surface enhanced resonance Raman spectroscopy and electrochemistry in nonaqueous media. Metallation of SAMs of the three mercaptoporphyrins was achieved in refluxing metal acetate solution, to different degrees. mTMTP monolayer was found to metallate easiest, which implies its molecular arrangement at the polycrystalline gold surface is different from the other two mercaptoporphyrins. The metallated porphyrin SAMs appeared to be capable of electrocatalysing oxygen reduction in acidic media. In the second part of this dissertation, free-standing ultrathin and thin films of the porphyrins linked by disulfides were reported for the first time. Obtaining free-standing organic thin fiims with such electronic and optical properties as possessed by porphyrins has been desirable but not successful before this research. Synthesis of porphyrin networks, such as disulfide-linked polymers, electropolymerized networks, and sized porphyrin networks was described. The free-standing ultrathin and thin disulfide-linked porphyrin films were formed by / oxidation of selected mercaptoporphyrins via interfacial polymerization using transition metal ions as the oxidant. Fabrication of these films was achieved by supercritical drying (also known as critical point drying). The two surfaces of the films appeared different. Spectroscopic, thermal and x-ray diffraction techniques were applied to characterize the free-standing porphyrin films. / Source: Dissertation Abstracts International, Volume: 56-08, Section: B, page: 4290. / Major Professor: Joseph B. Schlenoff. / Thesis (Ph.D.)--The Florida State University, 1995.

We have attempted to participate in the advancement of polymer science through active research into the preparation of poly(aryleneethynylene) polymer chains (PAEs) (Figure 1). We have also investigated some other similar polymer systems. &parl0; - - ≡- Ar-≡ -Ar- ≡ -Ar- ≡-Ar -≡ - &parr0;n Figure1.General structureofap olyaryleneethynylene Poly(aryleneethynylene) systems contain carbon-carbon triple bonds within the main chain of the polymeric backbone and compose one of the relatively few groups of electrically conducting organic polymers. Interest in electrically conducting organic polymers was spawned by the discovery by Hatano et al. in 1961 that polyacetylene conducted an electric current, although it was about ten years later that serious research began. These materials are of synthetic interest not only for the possible exploitation of their expected electrical behavior, but also because they will potentially exhibit third order non-linear optical as well as photoluminescent properties. Poly(aryleneethynylene)s also display high thermal stability There are two major obstacles associated with poly(aryleneethynylene)s. The first is that without modification, the compounds typically exhibit very low solubility in organic solvents or water. The lack of solubility makes the processing and characterization of these types of polymers very difficult. The second obstacle is that the traditional method for PAE preparation (palladium catalyzed coupling of aromatic dihalides with terminal acetylenes) is laborious and usually utilizes rather harsh reaction conditions and/or less than desirable organic solvents (i.e. pyridine, dioxane, THF, etc.). Therefore, our work has concentrated on developing PAEs that are more soluble in organic and/or aqueous solvents, as well as modifying the methods of their preparation such that they are more easily performed and the conditions are less severe. We have tried to design novel materials in addition to incorporating desired qualities in both the polymers synthesized as well as the methods in which they have been prepared This research project has produced a series of highly conjugated poly(aryleneethynylene)s. These materials have been prepared through the careful selection and synthesis of polyhalogenated aromatic monomers and polymerized through the use of traditional and modified palladium catalyzed coupling reactions. The polymers generated from this research have a variety of physical characteristics that are potentially valuable in selected polymer applications. These new materials have been prepared without the need for the extensive monomer modification that is often associated with highly functional polymer species The preparation of the polymers for this project has led to the development of a very useful modification of the well known palladium mediated Sonogashira coupling reaction---the acetylene gas reaction. The procedure is mild with regard to temperature and solvent demands and is very flexible in these regards as well. The procedure can be performed at room temperature under completely aqueous conditions to produce a high weight poly(aryleneethynylene) Therefore, we have prepared several new polymer species as well as developed a unique polymerization method for doing so / acase@tulane.edu

Recent developments in the lateral motion model for polymer melt dynamics are presented. The model rests on the assumption that the lateral motion of the chains plays a significant role in the dynamics of linear chain melt polymer systems. The lateral chain motion requires significant correlation in the displacements of the chains, because pairs of nearby chains have a large number of contacts on average and, as a chain moves along the backbone of another chain, its motion is impeded by the presence of other chains. The analysis provides a description of the short time dynamics and of the crossover from this early time regime to a highly entangled dynamics. The crossover time is found to be independent of chain length. The coupling between the repetitive motion of the chains and their lateral motion, as well as long range correlated many chain motions, are also considered. The predictions of the theory for the scalings of the terminal time and the diffusion constant for the center of mass with chain length are in excellent agreement with experimental data. The constants in the theory are optimized using theoretical analysis and computer simulations, and the predictions of the model are compared with experimental diffusion constant data for polyethylene, poly (ethylene oxide) and poly (dimethyl siloxane) polymer melts with excellent results. Approximate analytical formulas are obtained for the center of mass diffusion constant dependence on molecular weight. They differ only slightly from the full calculations, and enable for easier comparison with experiment / acase@tulane.edu

Polyelectrolyte conformation, interactions and hydrodynamics show a marked dependence on the ionic strength (C$\sb{\rm s}$) of the medium, the concentration (C$\sb{\rm p}$) of the polymer itself and their charge density ($\xi$). The apparent electrostatic persistence length obtained from static light scattering varied approximately as the inverse square root of C$\sb{\rm s}$ for highly pure, high molecular weight hyaluronate (HA) as well as for variably ionized acrylamide/sodium acrylate copolymers (NaPAA), and linearly with $\xi$. The experimental values of persistence length and second virial coefficient (A$\sb2$) are compared to predictions from theories based on the Debye-Huckel approximation for the Poisson-Boltzmann equation and on excluded-volume. Although the mean square radius of gyration ($\rm\langle S\sp2\rangle$) depended strongly on C$\sb{\rm s}$. $\rm\langle S\sp2\rangle$ decreasing with increasing C$\sb{\rm s}$ for both HA and NaPAA indicating clear evidence of polyion expansion, dynamic light scattering values of the translational diffusion coefficient (D) remains constant when extrapolated to infinite polymer concentration for both the polymers. The behavior of D is compared to predictions from coupled mode theory in the linear limit. The effects of NaOH on the conformations, interactions, diffusion and hydrolysis rates of HA are characterized in detail using static, dynamic and time-dependent light scattering supplemented by size exclusion chromatography (SEC). For the HA $\rm\langle S\sp2\rangle,\ A\sb2$ and the hydrolysis rates all resemble superposing titration curves, while the D remains independent of both the concentration of NaOH, and the contraction of $\rm\langle S\sp2\rangle$. The indication is that the interactions, conformations and the hydrolysis rates are all controlled by the titration of the HA hydroxyl groups by the NaOH to yield -O$\sp-$, which (i) destroys single strand hydrogen bonds, leading to de-stiffening and contraction of the HA coil and a large decrease in intermolecular interaction, and (ii) slowly depolymerizes HA. The experimental results of HA depolymerization is compared to predictions from the theory of random scission. PGM depolymerization is carried out with (i) NaOH, (ii) hyaluronidase, (iii) HCl. These agents degraded the polymer in different ways. NaOH apparently stripped off the GAG chains from the protein backbone. Hyaluronidase seemed to randomly cleave the GAG sidechains, while HCl both stripped the GAG sidechains and randomly cleaved the protein backbone. Time dependent static light scattering of each degradation mechanism traced out its own characteristic signature of reciprocal scattered intensity versus time, models for which are presented. This technique allows degradation mechanisms, associated rates and percentage of material in the backbone and sidechains to be determined. The presence and removability of the 'extraordinary' diffusional phase (EP) at low ionic strength are investigated exhaustively for HA, NaPAA, polystyrene sulfonate, poly(L)lysine, heparin and chondroitin sulfate. The EP is found to be always removable by filtration through a sufficiently small pore-size membrane / acase@tulane.edu