M.S.

Experimental measurements ol N₂ resonant charge transfer cross sections were performed. It was found that the energy of electrons used to produce the N₂⁺ ions is an important variable with respect to cross section. An examination of the experimental precision was performed and it was found that the precision of measurement was insufficient to determine the exact form of this relationship. The effect of ion energy (collisional energy) was too small to be seen. Modulated detection was used to improve precision and permit measurement at high noise levels. A description of the apparatus is provided. Consideration of other systems and the suitability of their resonant charge transfer reactions for experimental investigation is discussed. Various theoretical models for estimation of cross section were examined. / M.S.

A method of analysis of the total sulfur in crude viscose rayon was developed. This consisted of extraction of the sulfur with sodium hydroxide solution, oxidation to sulfates with bromine, and precipitation as barium sulfate. This method is accurate to one percent. A more rapid method for the analysis of total sulfur consists of boiling the rayon in a dilute solution of sodium sulfite followed by titration of the sodium thiosulfate produced. The total sulfur may also be roughly estimated by observation under the microscope. The presence of even a trace of sulfur may be observed by this method. The form of the sulfur in the crude viscose rayon was shown to be entirely elementary sulfur. This was accomplished by extracting the sulfur with methyl alcohol and showing that the extract consisted of pure elementary sulfur. This result was supported by the series of experiments in Section V. The reason for the incomplete removal of the sulfur from the rayon by organic solvents for sulfur was shown to be due to the inability of the solvent to penetrate into the cellulose structure. When the rayon was swelled by soaking in water, the solvents were able to penetrate into it and thus remove all the sulfur. Extraction of rayon in a swollen condition for 20 minutes with acetone completely desulfurized it. This treatment did not appear to have any effect on the tensile strength or elongation. The use of acetone or methyl alcohol as a desulfurizing agent was shown to be feasible. The low results in the case of sample number one may have been due to the reaction of the sulfur with sodium sulfite being incomplete, or, perhaps, due to the oxidation of some sodium thiosulfate by the air during the long time of boiling. The method in general is not very accurate due to the difficulty of getting a good end point in the titration. The estimated accuracy is about five percent. However, this method is recommended as a method of analysis of the total sulfur in crude viscose rayon which may be used in the control laboratory of a rayon plant, since it was the simplest and most rapid encountered during this work. In general the results indicate that the sulfur in the rayon reacted with sodium sulfite according to the reaction S + Na₂SO₃ → Na₂S₂O₃ / M.S.

The reaction between 2 acetamino 6 amino benzo thiazole and chloroiridio acid is not sensitive enough to be of importance as a colorimetric quantitative reaction. IrCl₆-- can be detected with this organic compound if iridium is present in as much as 0.02 mg. per ml. of solution providing ferric iron is absent. If ruthenium is present it must be removed before the test for the iridium anion can be made. / M.S.

M.S.

M.S.

M.S.

While theoretical treatments of liquid spreading on solid surfaces can be found in abundance in the literature, relatively few experimental studies have been performed. This study focused on the experimental detection of polydimethylsiloxane spreading on polymer surfaces in the spreading regime where gravitational and inertial forces are negligible. The techniques of x-ray photoelectron spectroscopy (XPS), reflection absorption spectroscopy (RAS), and contact angle analysis were used to investigate this problem. XPS analysis indicated that the surface spreading or "creeping" was very slow, moving only several centimeters per several hundred hours in some cases. An interesting observation was that the spreading film seemed to reach a "steady state" concentration when covering an area. Similar results were seen for both horizontal and vertical substrate surfaces with XPS, and there seemed to be a substrate dependence. Angular-dependent XPS analysis revealed that the film was very thin (<20A) and not a complete layer. Contact angle analysis was used to monitor the siloxane movement, although there was a contact angle dependence on x-ray exposure time, indicating cross-linking of the surface film. Contact angle variations were also used to show that the film characteristics may be dependent on the nature of the polymer substrate. Reflection absorption spectroscopy was used to investigate thin substrate polymer films, and it was shown that theoretical predictions of absorption band intensity correlated reasonably well with the experiment. This technique was also used to investigate the surface siloxane layer and indicated that under some conditions, the orientation of the surface silicone layer may be occurring. / M.S.

It was desired to isolate and identify the flavor material obtained by hydrolysis and oxidation from Acer saccharum wood. This has been done and the material is shown to be 3-methoxy-hydroxycinnamic aldehyde or coniferyl aldehyde. It has been shown definitely that the flavor is not due to vanillin. An extraction procedure has been worked out for the best isolation of the material without the losses attendant upon the methods previously given. It has been shown that previous methods of isolation may destroy some of the material by virtue of the alkaline reagents used. A number of products have been shown to be present in the wood extract and to be extractable from this aqueous wood extract by means of chloroform. Among these are lignin-like materials, gums, a phenol thought to be guaiacol, and malic and probably vanillic acid. Ground-work has been done for further investigation into the materials obtained by hydrolysis of the wood. / M.S.

M.S.