Polyarylethers have been synthesized earlier via nucleophilic aromatic substitution, using aqueous caustic and polar solvent such as DMSO. This route even though rapid, suffers from serious limitations. We have modified this procedure considerably to synthesize a wide variety of high molecular weight polyarylethers. Our methodology utilized a higher boiling solvent namely N-methylpyrrolidone, a weak base such as K₂CO₃ and an azeotroping solvent such as toluene. Such a process allows one to synthesize the polymer in situ. We have also shown the feasibility of utilizing the procedure to synthesize functionally terminated controlled molecular weight oligomers. High molecular weight tetramethyl substituted bis A arylene ether ketones, sulfones, and nitrile functional polyarylethers have been synthesized successfully. The ketone containing tetramethyl bisphenol A polymers has been found to be a photocrosslinkable resin and hence a potential candidate as a negative photo-resist for electronic materials. Investigation of the thermal behavior of these polymers have indicated considerable interchain forces to be operating with the nitrile functional polymers. The nitrile functional polymers have been modified via hydrolysis to produce more hydrophilic and thermally stable amide functional polymers. Attempts at crosslinking the pendant nitrile groups via cyclization using Lewis acid were not as successful as expected. However, the use of the pendant nitrile group as a site for anionic grafting has been demonstrated. A wide variety of crystalline poly aryl ether ketones have been synthesized by using a modified synthetic strategy in which an amorphous polymer is first synthesized to high molecular weight in NMP and then chemically modified to produce crystalline polymers. All amorphous ketone functional polymers have been modified to produce, more hydrophilic, less thermally stable but potentially crosslinkable, alcohol functional polymers. All the homo and copolymers synthesized have been characterized at the molecular level by solution ¹³C NMR and FT-IR spectroscopy. Proton NMR was also used for compositional analysis. All polymers were also characterized thermally by DSC; other thermal characterization techniques such as TG and TMA have also been used. Molecular weight characterization included intrinsic viscosity measurement on all polymers and selective utilization of GPC. For crystalline insoluble polymers, solid state ¹³C NMR was used extensively for molecular level characterization. Wide angle x-ray measurement and DSC have been obtained in order to prove the existence and the level of crystallinity in these samples. Limited characterization by SEM and EDAX was also conducted, primarily to gain information concerning the surface structure. / Ph. D.

Measurements of the nonlinear viscoelastic behavior of two adhesives, FM-73 and FM-300, are presented and discussed. Analytical methods to quantify the measurements are given and fitted into a framework of an accelerated testing and analysis procedure. The single integral model used is shown to function well and is analogous to a time-temperature stress-superposition procedure (TTSSP). Advantages and disadvantages of the method accessed with the latter residing primarily with the nature of the creep power law which is utilized. / M.S.

Field studies were conducted to determine the effects of wheat and barley residue and tillage method on the emergence and growth of oilseed sunflower. Additional studies were executed to test the effects of wheat, barley, and rye root and straw residue and the effects of cold water extracts of wheat and barley straw on the germination and growth of sunflowers in controlled environments. Sunflower planted into tilled and no-tilled three week old wheat residue showed no differences in emergence from those planted into followed plots. Sunflower leaf numbers at four weeks were reduced in wheat residue and in no-till plots. Differences in maturity due to tillage were no longer visible at eight weeks. Sunflower planted into tilled and no-tilled barley straw immediately after barley harvest showed a significant reduction in emergence due to barley residue and to minimum tillage. Significant differences due to treatment for many variables in the barley/sunflower plots could be attributed to low values obtained in no-till fallow treatments. Minimum tillage of barley residue plots reduced sunflower height at six weeks as compared to minimum tilled fallow plots. At eight weeks all minimum tilled plots were more mature than no-tilled plots. Rye and wheat root and surface straw residue delayed, and barley residue inhibited the emergence of confectionary sunflower in pots. Rye, wheat, and barley residue inhibited the emergence of oilseed sunflower. Wheat and rye residue depressed the growth of oilseed sunflower and wheat residue depressed the growth of confectionary sunflower seedlings grown in pots. In most cases, the extract of 1:10 dilution of wheat and barley straw reduced sunflower growth. Few significant differences in sunflower growth were seen among the 1:100, 1:1000, or 1:10,000 concentrations of any one small grain variety. Some low concentrations of residue extracts were observed to enhance sunflower growth as compared to control treatments. / M.S.

In the course of studies on degradation of dietary fiber by the human colon bacteria, a number of Bacteroides strains from the human colon have been found to degrade polygalacturonic acid and/or pectin. Four of these strains were examined for presence of polygalacturonate lyase (PGAL). The Bacteroides strains studied synthesized inducible, cell-associated PGALs when the bacteria were grown on media containing polygalacturonic acid or on peanut cell wall (a prototype dietary fiber with a uronide content of 14.0%) as the sole carbon source. No PGAL activity could be detected in cultures grown on media containing glucose or D-galacturonate. The PGALs produced by the four Bacteroides strains had properties similar to other bacterial PGALs: An alkaline pH optima (8.5), stimulation of activity by calcium ions. complete inhibition by ethylenediaminetetraacetic acid (EDTA), preference for polygalacturonic acid as a substrate over pectin, and accumulation of unsaturated products which absorb at 235 nm. The Bacteroides PGALs catalyzed partial degradation of the uronides of peanut cell wall substrate, but at a slower rate compared to their action on polygalacturonic acid substrate. / M.S.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Rat pups (Rattus Norvegicus) were exposed to saccharin through suckling dams whose drinking water had been adulterated during lactation. Behavioral evidence is reported that the saccharin penetrated the milk and was detectable by the pups. Preexposure to saccharin did not influence the effects of taste aversion training conducted with a saccharin CS when the pups were 18 days old. Taste aversion learning was weaker in the pups than in adults run in the same study. No effect was found for CS concentration on taste aversion learning for the pups or the adults. / M. S.

The friction and wear behavior of three thin polyimide films of known chemical structure was tested. An attempt was made to correlate differences in chemical structure, primarily the presence of flexible linkages and highly polar side groups, to differences in tribological properties. The wear test results showed lowest wear for the polyimide with the flexible oxygen linkage. The wear mechanism was deduced to be fatigue since wear did not occur immediately and a strong correlation was noted between wear rate and elastic modulus. Increasing sliding speed increased both wear rate and friction coefficient. The friction results showed highest friction for the polyimide with the highest density of polar side groups. Even though some effects of the deformation component of friction were seen, the adhesive component of friction predominated. / Master of Science

The modification of polyimide films by tin-complex incorporation has been studied with the aim of producing materials with the mechanical and thermal properties of polyimide with enhanced electrical properties. A variety of Sn(II) and Sn(IV) complexes have been incorporated into BTDA/ODA (3,3 14,4 1-benzophenonetetracarboxylic acid dianhydride / 4,41- oxydianiline) and PMDA/ODA (pyromellitic dianhydride/4,4 1 -oxydianiline) derived polyimides in a 1:4 (complex/polymer repeat unit) molar ratio. Tin-complex incorporation was seen to have a variety of effects upon polyimide properties, depending upon the particular tin-complex employed. All films produced were thermally stable with decomposition temperatures> 500°C. Most films were homogeneous and flexible. / Master of Science

The class of real nxn matrices M, known as K-matrices, for t which the linear complementarity problem w-Mz=q, w≥O, z≥O, w^tz=O has a solution whenever w-Mz=q, w≥O, z≥O has a solution is characterized for dimensions n<4. The characterization is finite and"practical". Several necessary conditions, sufficient conditions, and counterexamples pertaining to K-matrices are also given. A finite characterization of completely K-matrices (K-matrices all of whose principal submatrices are also K-matrices) is proved for dimensions < 4. / M.S.

Thermosetting polyurethane films were prepared from solution by crosslinking hydroxypropyl lignin derivatives with diisocyanates. The network structure, characterized by the crosslink density, was controlled by two variables: the hydroxy content of the lignin polyol and the molar ratio of NCO:OH. In addition, the effect of network structure on thermal and viscoelastic properties was determined. Both the thermal and viscoelastic properties of the polyurethane films followed the trends found for crosslink density. For those films prepared from the various polyols with reduced hydroxy functionality, T_g was found to vary linearly with the extent of crosslinking as well as with the T_g of the polyol from which it was prepared. As the NCO:OH ratio was increased, the major difference in T_g occurred within the range from 1:1 to 3:1. Similar trends were noted for the viscoelastic properties in both instances. However, it was apparent that the sol fraction contributed significantly to the overall properties of the network, particularly at the high weight fractions. Fracture surface analysis of model substrates (cellulose acetate and cellulose tri-acetate) bonded with a lignin-polyisocyanate resin by Electron Spectroscopy for Chemical Analysis (ESCA) revealed the formation of interfacial bonds on the surface of the cellulose acetate adherend. Furthermore, it was indicated that failure occurred well within the bulk of the cellulose acetate while interfacial failure was apparent for the cellulose tri-acetate model. While mechanical attachment is unquestionably a contributing mechanism, the formation of interfacial bonds should significantly contribute to the performance of bonded joints for this particular adhesive system. / M.S.