Steel is a material with a high tensile shear strength and is relatively inexpensive to produce. Further, it is widely used in industry and its use in adhesive bonding applications is increasing. Adhesively bonded structures offer several advantages over mechanical fastening such as reductions in cost and weight and also provide uniform stress distribution. The goal of this research is to study the effect of four metal alkoxides on the adhesive bonding of steel. The topography and chemical composition of gritblasted, alkoxide primed surfaces were determined using primarily scanning electron microscopy and x-ray photoelectron spectroscopy. Gritblasted steel was primed with the metal alkoxide solutions and then bonded with both polyethersulfone (thermoplastic) and FM 300U, a structural epoxy (thermoset). Bond durabilities were studied using wedge specimens. The two aluminum alkoxide primed steel surfaces generally showed slower crack propagation than titanium and silicon alkoxide primed surfaces. Bond strength information was obtained from lap shear joints that were primed with aluminum tri-sec-butoxide, titanium (IV) butoxide and control samples where no primer was used. Statistical analysis showed that there were significant differences in bond strengths, with the aluminum alkoxide primed surfaces showing higher breaking strengths. Further, the effect of applied stress and temperature on bond strength was determined. Lap shear joints that were primed and unprimed and bonded with PES and FM 300U were loaded to 10-40%, depending on the ultimate breaking strength and placed in a stress durability tester (immersion in deionized water at 80°C). A significant decrease in breaking strength was observed between the stress durability samples and the lap shear joints tested at room temperature. The failure surfaces of wedge, lap shear and stress durability samples were analyzed using scanning electron microscopy, energy dispersive x-ray analysis, x-ray photoelectron spectroscopy and Auger electron spectroscopy. / Master of Science

M.S.

In conclusion it may be said that contrary to the results of the fractionation obtained from the fractionation of cellulose xanthate diethylacetamide by Fink, Stahn, and Matthes; the results obtained here indicate that there is a definite variation of the degree of substitution from fraction to fraction. And that therefore cellulose xanthate as commercially prepared is heterogeneous with respect to degree of polymerization and degree of substitution. There does seem to be a definite relationship of some sort between the two factors, the degrees of polymerization and substitution. Fractionation as accomplished here is controlled by both the degree of polymerization and the degree of substitution and at no time is it likely that either factor is independent of the other. In fact, there is a strong probability that the degrees of polymerization determined are only apparent degrees of polymerizations controlled by the variations in substitution. It is known that the viscosity of compound in solution is a function of the degree of substitution; to what extent is unknown. / M.S.

M.S.

Electrochemical and infrared spectral data for a number of octahedral systems of the type LM(CO)₅ (M=Cr, Mo) and W; L=pyridine and quinoline), L₂M(CO)₄ (M=Cr, Mo, and W; L₂ =ethylenediamine, (pyridine)₂, and bipyridyl), (LM(CO)₄)₂ (M=Cr, Mo, and W; L=As(CH₃)₂ and P(CH₃)₂) and (LFe(CO)₃)₂ (L=SCH₃ , P(CH₃)₂ , and As(CH₃)₂) before and after electrochemical reduction are presented. Force constants are calculated using the Cotton-Kraihanzel force field and the results discussed in terms of sigma and pi-bonding. Infrared spectral data before and after electroche~ical reduction are also reported for a number of iron-olefin complexes of low symmetry. / M.S.

Many of the properties of ethyl cellulose that make it useful in different ways are a result of the varying lengths of the cellulose chains arranged within the chain bundles. This investigation was undertaken in order to find a method of separating these ethyl cellulose chains into more homogeneous groupings and to determine the distribution of chain lengths. The conditions and procedure are to be so determined that the results from one fractionation may be duplicated in succeeding ones. A commercial grade of ethyl cellulose can be fractionated according to length of the chain, degree of polymerization, by the method worked out in this investigation. At the present time is it not known what effect dissolving the ethyl cellulose in 80% acetic acid and the subsequent treatments have had on the ethoxy content. It is possible for the degree of substitution to decrease from the first through the last fraction, but this is not considered likely in view of the distribution curve obtained. / M.S.

M.S.

6-Carboethoxybicyclo [3.3.0] oct-6-en-2-one has been prepared by the intramolecular [4+1] cyclopentene annulation method. This compound and its precursor, 6-vinyl-6-carboethoxybicyclo[3.1.0]hexan-2-one were attained as the necessary standards for the investigation of the course of intramolecular Michael addition-alkylation sequence of l-phenylsulfonyl-6-carboethoxyocta-5,7-dien-2-one. / M.S.

1. From a study of the system salicylic acid-biphenyl it was concluded that there was no compound formation in the system. The solution is very nearly ideal, having an eutectic temperature of 67.6℃ at a mole fraction of .903 for the biphenyl. 2. The system salicylic acid-diphenylamine was studied and no compound formation was found to be present. The system and no compound formation was found to be present. The system is not as ideal as the salicylic acid-biphenyl system, but follows the ideal solution curve fairly well. The system has an eutectic temperature of 48.5℃ at .926 mole fraction of diphenylamine. / M.S.

M.S.