The object of this research was the development of on-line methods for the determination of the degree of substitution of cellulose esters. The focus of the effort was on the application of a Fourier transform infrared spectrometer (FT-IR) as an in-line detector for quantitative gel permeation chromatography (GPC). GPC/FT-IR has been used in the analysis of polymeric materials in the past, but not for quantifying the substituent content of cellulosics. This work has identified the infrared asymmetric nitrate absorptions of cellulose nitrates observed in THF and acetonitrile solutions. Independent absorptions for the primary nitrate at C₆ and secondary nitrate at C₃ were observed at 1651 cm⁻¹ and 1639 cm⁻¹ respectively. In addition, a third absorption at 1667 cm⁻¹ was observed to be dependent upon the degree of nitration of the cellulose nitrate. This absorption was found to be due to steric hindrance between secondary nitrate groups on the C₂ and C₃ sites. The infrared absorptions of cellulose acetate butyrates in THF, acetonitrile, and methylene chloride were also characterized. Separate absorptions for the acetyl and butyryl C-O-C asymmetric stretch were observed at 1235 cm⁻¹ and 1176 cm⁻¹ respectively. In acetonitrile and methylene chloride the carbonyl asymmetric stretching mode frequency observed at ≈1753 cm⁻¹ was found to be dependent upon the extent of acetyl substitution. This work developed a method for the quantitative determination of the degree of nitration of cellulose nitrates as a function of the polymer molecular weight using the asymmetric nitrate stretch. Methods for the determination of the acetyl and butyryl substitution of cellulose acetate butyrates were developed as well. Examples of each method applied to real world samples were carried out. / Ph. D.

The chiroptical properties of isotropic solutions, cholesteric liquid crystals and solid films prepared from selected cellulose derivatives are investigated by optical rotary dispersion (ORD) and circular dichroism (CD). Optical activity from intrinsic molecular dissymmetry, polymer conformation and cholesteric reflection properties are considered. / The chiroptical properties of cholesteric liquid crystals are interpreted according to deVries' theory. Lyotropic liquid crystalline phases formed by (hydroxypropyl)cellulose in methanol display anomalously high optical rotation at low wavelengths. The anomalies disappear on the addition of a dipolar aprotic solvent, and are absent for the ethyl ether derivative of the polymer, indicating a chiral hydrogen bonded structure is contributing to the optical activity. / Investigation of the chiroptical properties of cellulosics by circular dichroism requires the presence of a suitable chromophore, either as a chain substituent or as an added dye. Congo red exhibits induced optical activity in dilute aqueous solutions of methylcellulose and cellulose oligomers, providing evidence for the presence of a helical conformation. CD spectra of two new biphenyl derivatives also exhibit exciton splitting characteristic of a helical arrangement of chromophores. Conformational dissymmetry is not indicated in spectra of cellulose acetate although the sign of carbonyl CD band is solvent dependent. The sign of this band is interpreted in terms of the orientation of the ester substituent relative to the anhydroglucose ring. Congo red, bound in cholesteric cellulose films prepared by the deacetylation of cellulose acetate cast from mesophase solution, shows induced optical activity which, in this case, reflects the cholesteric nature of the matrix. Similar results for cellulose gels regenerated from LiCl/N,N-dimethylacetamide solution indicate that cellulose adopts a supramolecular helicoidal arrangement on slow precipitation from solution. / The optical properties of the thermotropic cholesteric liquid crystalline phase formed by a new cellulose derivative, (ethoxypropyl)cellulose, are examined by circular reflectivity measurements. / The cholesteric reflection properties of mesophase solutions of cellulose acetate in trifluoroacetic acid are characterized. The polymer undergoes rapid trifluoroacetylation in this solvent and the presence of trifluoroacetate substituents alters the handedness and the magnitude of the pitch. Although the pitch is sensitive to the nature of achiral substituents, it is not influenced by the addition of chiral solvents. (Abstract shortened with permission of author.)

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1. A two prism spectrograph has been designed and oonstruoted with which it is believed Raman spectra may be obtained. 2. Attempts have been made using the spectrograph to obtain Raman spectra. These attempts, are as yet unsuccessful. / M.S.