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Synthesis and characterization of tractable linear metal beta-diketone coordination polymersOchaya, Ven Oryem 01 January 1993 (has links)
New soluble linear cobalt(III) and chromium(III) $\beta$-diketone polymers have been prepared and characterized. Attempts to prepare linear coordination polymers analogous to the synthetic organic counterparts have historically posed serious problems for chemists particularly as a result of their intractability. In this study, bis($\beta$-diketonates) of the metal were first prepared and then allowed to react with sulfur halides of the form SCl$\sb2$ or S$\sb2$Cl$\sb2$ to yield thio- or dithio-bridged polymers, with the bridging occurring through the 3-carbons of the 2,4-diones. The polymers were found to be extremely soluble, with moderate molecular weights of at least 15,000 (as determined by NMR end-group analysis and viscosity measurements). GPC results were less satisfactory; they indicated polystyrene was not good as a standard for these polymers. Characterization of the materials was accomplished by Fourier-transform infrared (FT-IR), $\sp1$H- and $\sp{13}$C-nuclear magnetic resonance (NMR), pyrolysis-gas chromatograph/mass spectroscopy (py-GC/MS) and ultraviolet-visible (UV-vis) spectroscopy. Micro-analyses, gel permeation chromatography (GPC), thermal gravimetric analysis (TGA) and viscosity measurements were also performed. The synthesized materials also showed different degrees of thermostability (to at least 250$\sp\circ$C) and volatility as shown by their thermograms. In general, the trifluoroacetyl acetonate polymers were found to yield the more volatile polymers, while the Co(III)-containing materials were generally less volatile than their Cr(III) counterparts. A secondary goal of the investigation was to establish the ability of these materials to undergo chain scission upon exposure to radiation, with the reduction in molecular weight based on GPC measurements. Upon irradiation, GPC results clearly showed degradation to lower molecular weight materials. This reduction in molecular weight is an essential characteristic and requirement for positive acting resists, a possible application for these compounds.
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A spectroscopic analysis of the structure of highly ordered polymersSavage, John David 01 January 1993 (has links)
The structure, morphology, phase transition behavior, and factors which govern the formation of helical crystalline syndiotactic polystyrene (sPS) have been investigated. The primary technique employed is vibrational spectroscopy, proven useful to obtain chain conformation distribution and chain and segmental orientation of polymers. Other techniques, such as wide angle X-ray diffraction and thermal analysis are used to characterize the crystalline state. Highly crystalline helical (TTGG) sPS has been prepared by isothermal growth from dilute solution, minimizing the amorphous structure. The crystals are observed to consist of a complexed structure of sPS and solvent molecules. Low frequency Raman spectra for sPS and their solvent complexes are reported. Although intramolecular, the phenyl ring torsion about the backbone is observed to be highly sensitive to the solvent complexed crystalline state and therefore the intermolecular ring environment. This suggests that such a band may be useful for examining the polymer-solvent specific interaction spectroscopically and therefore the mechanism of formation of the helical crystalline phase in sPS. The morphology of as-grown highly crystalline sPS/ethylbenzene mats consists of ribbon-like structures, which are irreversibly disrupted upon the expulsion of solvent from the crystal lattice. Complete molecular reordering during the helix to trans phase transition cannot be accounted for by cooperative bond rotation, consistent with the irreversible nature of the transition, and further emphasizing the critical role of solvent in the formation of helical crystallites. Crystalline syndiotactic polystyrene/solvent complexes prepared from different solvents exhibit a variety of different structures, as indicated by wide angle X-ray diffraction and thermal analysis. Differences in chain packing associated with these structures are reflected in the band shape and intensity of the low frequency phenyl ring torsional vibration. In addition, polarized infrared spectra show that phenyl rings of solvent molecules pack parallel to the syndiotactic polystyrene phenyl rings in these crystalline syndiotactic polystyrene/solvent complexes. A normal vibrational analysis is performed for the helical (TGGT) form of sPS. The calculated frequencies agree well with the observed infrared and Raman spectra, including conformationally sensitive bands.
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Aryl mesylates in nickel (0) catalyzed homo- and cross coupling reactionsBae, Jin-Young January 1995 (has links)
No description available.
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The processing/structure/property relationships of polyvinyl alcohol hydrogelsTrieu, Hai Hong January 1995 (has links)
No description available.
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Structure and viscoelasticity of proteoglycans and glycoproteinsSoby, Lynn Margaret January 1990 (has links)
No description available.
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Reactive processing and material characterization of thermoplastic and thermoset polymers and their compositesNing, Xin January 1991 (has links)
No description available.
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Non-centrosymmetric Langmuir filmsOu, Shih-hong January 1993 (has links)
No description available.
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MODIFICATION OF CALCIUM ALGINATE MEMBRANES WITH MONTMORILLONITE CLAY TO ALTER THE DIFFUSION COEFFICIENTVALE, JAMES MICHAEL January 2004 (has links)
No description available.
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Synthesis and characterization of metal coordination polymers through condensation and chelation polymerizationsCronin, Jon Andrew 01 January 1995 (has links)
To further elucidate the effects of atomic and bonding variations within metal coordination polymers on the properties of the bulk polymer, two new metal coordination polymers containing zirconium(IV) have been synthesized and characterized. Through the condensation polymerization of tetrakis(salicylaldhydato)zirconium(IV), Zr(sal)$\sb4$, and 3,3$\sp\prime,4,4\sp\prime$-tetra-aminodiphenylmethane or the chelation polymerization of Zr(sal)$\sb4$ and N,N$\sp\prime,\rm N\sp{\prime\prime},N\sp{\prime\prime\prime}$-tetrasalicylidene-$3,3\sp \prime,4,4\sp\prime$-tetraaminodiphenylmethane, H$\sb4$tstm, the polymer catena-poly (zirconium(IV)($\mu-\rm N,N\sp\prime,N\sp{\prime\prime},N\sp{\prime\prime\prime}$-tetrasalicylidene 3,3$\sp\prime,4,4\sp\prime$-tetraaminobiphenylmethanato-O,N,N$\sp\prime,\rm O\sp{\prime}$:$\rm O\sp{\prime\prime},N\sp{\prime\prime},N\sp{\prime\prime\prime},O\sp{\prime\prime\prime}$)), (Zr(tstm)) $\sb{\rm n}$, was prepared. Similarly, reaction of Zr(sal)$\sb4$ with 3,3$\sp\prime,4,4\sp\prime$-tetraaminodiphenylsulfone yielded catena-poly (zirconium(IV)($\mu$-$\rm N,N\sp\prime,N\sp{\prime\prime},N\sp{\prime\prime\prime}$-tetrasalicylidene-$3,3\sp\prime,4,4\sp\prime$-tetraamino-biphenylsulfonato-$\rm O,N,N\sp\prime,O \sp\prime$:$\rm O\sp{\prime\prime},N\sp{\prime\prime},N\sp{\prime\prime\prime}, O\sp{\prime\prime\prime})\rbrack$, (Zr(tsts)) $\sb{\rm n}$. Due to the instability of N,N$\sp\prime,\rm N\sp{\prime\prime},N\sp{\prime\prime\prime}$-tetrasalicylidene-$3 ,3\sp\prime,4,4\sp\prime$-tetraaminodiphenylsulfone,$\ H\sb4$tsts, in the polymerization solvent dimethylsulfoxide, the reaction of Zr(sal)$\sb4$ and H$\sb4$tsts yielded only oligomeric material. Molecular weight determinations by GPC on fractionated polymer samples in N-methylpyrrolidinone gave polystyrene equivalent molecular weights in excess of 13,000 for (Zr(tstm)) $\sb{\rm n}$ by both synthetic procedures described above and 8,700 for (Zr(tsts)) $\sb{\rm n}$ prepared via condensation polymerization. After capping the metal ends of the polymers with a N,N$\sp\prime$-bis(5-tert-butylsalicylidene)-1,2-diaminobenzenato(2-) group, end group analysis by $\sp1$H-NMR corroborated these data. The polymers were also characterized by IR and UV-vis spectroscopies. Thermal analyses of the polymers showed that they are air stable to greater than 400$\sp\circ$C. These new polymers were compared to another zirconium polymer, catena-poly (zirconium(IV)($\mu$-$\rm N,N\sp\prime ,N\sp{\prime\prime},N\sp{\prime\prime\prime}$-tetrasalicylidene-$3,3\sp\prime$-diaminobenzinato-$\rm O,N,N\sp\prime,O\sp\prime{:}O\sp{\prime\prime},N\sp{\prime \prime},N\sp{\prime\prime\prime},O\sp{\prime\prime\prime})\rbrack$, (Zr(tsdb)) $\sb{\rm n}$, and their cerium(IV) analogs, (Ce(tsdb)) $\sb{\rm n}$, (Ce(tstm)) $\sb{\rm n}$, and (Ce(tsts)) $\sb{\rm n}$. Films of the polymers cast on chrome-plated steel were found to be continuous by scanning electron microscopy. Electrical experiments on films of the six polymers cast on glass gave conductivities of 10$\sp{-7}$ S/cm. These conductivities were increased by a factor of 10$\sp{4}$ by doping with iodine.
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Functionalised polymers by surface modification using diaryl carbenesAphaiwong, Apichat January 2014 (has links)
This thesis is concerned with the synthesis of diazo compounds for the introduction of various functional groups on the surface of polymers by means of carbene insertion and diazonium coupling. Characterisation and investigation of their properties were conducted. A library of functionalised polystyrene beads containing pyridine rings has been established for the coordination of metal ions and metal complexes. The pyridyl system on the surface has demonstrated its capability to bind with zinc complexes of bis(thiosemicarbazones) and release the corresponding copper complexes upon transmetallation. A spiropyran derivative has been introduced onto the surface of polystyrene and polyethylene terephthalate. The chromophore on both polymers exhibited photoswitchability as determined from colour change and wettability. Polystyrenes with either pyridine or spiropyran units have been investigated for reversible immobilisation of bioactive species. Materials coated with penicillin V gave significant inhibition zones in antibacterial assays, showing efficacy in drug delivery. Finally, a range of diazo compounds with different substituents has been synthesised and their thermal stabilities have been assessed by differential scanning calorimetry technique.
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