ALKYD RESIN THESIS

Because of the difficulty of transferring ether solutions quantitatively, several solutions were prepared by weighing samples of the anhydride and dis solving them and then running the spectra as soon as possible to avoid concentration changes due to evaporation. Almost all the work up to this time, has been directed toward chalking in modified glycerol phthalate resins. Appreciation is also expressed to the General Motors Corporation for the Fellowship w hi c h made this work possible and to the Renshed-Mason Company for formation of the resins used in this stu d y. With proper modification they may be applied readily by all methods; they may be either baked or air dried; they may be formulated to be extremely fast drying or to provide a heavy duty weather proof coating. Because of the difficulty of transferring ether solutions quantitatively, several solutions were prepared by weighing samples of the anhydride and dissolving them and then running the spectra as soon as possible to avoid concentration changes due to evaporation. This was done by measuring the absorbance of solutions of known concentration in cells of known thickness.

A second set of samples was irrradiated in wet oxygen. Swern, Daniel, et al. The mixed solvent systems described in Chapter II give excellent results in the carbonyl region. Measurement of Molar Absorptivities Molar absorptivities of phthalic acid, phthalic anhydride, and Resin A were measured at 5. In an effort to determine if a pero:

The resin used was an unmodified glycerol phthalate which will be fesin as Resin A throughout the rwsin of this paper. In order to determine the effect of these modifiers on the rate of degradation, films of about the same t h ickness of Resins A, B, and C Table 1 were prepared an d irradiated in a dry nitrogen atmosphere at 70 2C.

Dugan, Beadle and Henick4 have used infrared spectrophotometry to follow the autoxidation of methyl linoleate by studying the 2.

alkyd resin thesis

Fhesis oxygen is present, this vast source of free radical initiators is responsible for the greatly increased rate. The samples were located about 10 cm. Appreciation is also expressed to the General Motors Corporation for the Fellowship which made this work possible and to the Renshed-Mason Company for formation of the resins used in this study. This procedure was not only wasteful of time but the spectra so obtained showed a degree of zlkyd in absorbance values which it was felt might be the result of non-reproducible sample positioning in the beam of the spectrophotometer.

  VTS UNI ULM DISSERTATION

An enlarged view of this holder is shown in Figure 3. It was submitted to the Dean of the College of Arts and Sciences and to the Graduate Council, and was approved as partial fulfillment of the requirements for the degree of Doctor thessi Philosophy.

The methods of determination of thinner films described in Chapter II gave erratic results. Peroxy benzoic acid, monoperoxy phthalic acid, and a series of their esters were prepared and their spectra were examined. To further eliminate errors due to solvent absorption, a cell of approximately the same thickness as the sample cell was filled with the solvent mixture and placed in the reference beam of the rsin. Comparison of Figures 4 and 5 was considered to constitute sufficient evidence for the identification of the degradation product as phthalic anhydride.

The first appearance of a band in the spect: The sodium chloride cells used in infrared an a lysis were calibrated by two independent methods. All subsequent irradiation experiments employed this holder. Resins provided in solidified form were dissolved in acetone. On the assumption that much of this scattering was the ersin of non-reproducible positioning of the samples on almyd spectrophotometer, a new sample holder was constructed which largely eliminated this source of error.

This method was checked by weighing a film of known area and calculating thickness from the weight, area, and density.

yhesis Its composition is shown in Table 1, and Figure 1 shows the infrared spectrum of this resin at the beginning of the irradiation. The conclusion to which the author is forced, in the light of this result, is that the degradation process consists of an initial photolytic cleavage of the polymer at the site of the ester linkage. Formulation of Alkyd Resins.

A study of some factors affecting the degradation of alkyd resins

Film Thickness for cm. As might be expected the rate is much faster in an oxygen atmosphere than with nitrogen, Some inferences about the role of water vapor in this reaction may be made by examination of the results of this irradiation in wet nitrogen.

  YVAIN ESSAY TOPICS

alkyd resin thesis

Analytical Procedures and Techniques The spectra recorded on the Perkin-Elmer, Model 21, were run under the following conditions: This erosion of the vehicle results in loss of reson due to scattering and absorption of light by particles of the pigment which are now on the film’s surface.

A 6 33 absorbance at 6. Dugan, Beadle and Henick have used infrared spectrophotometry to follow the autoxidation of methyl linoleate by studying the 2. This dissertation was prepared under the direction of the chairman of the candidate’s supervisory committee and has been approved by all members of that committee.

A study of some factors affecting the degradation of alkyd resins

Figure 4 shows this region of the polymer spectrum at various stages in the irradiation. It was reasoned that if all the ester which disappeared from the film were converted to anhydride and no other aromatic products were formed, then the following general equation would hold: Use of the calibration curve permitted rapid evaluation of the thickness of films whose thickness was on the order of 10O3 cm.

The change of slope near 50 hours, it is felt, indicates the build-up of a layer of phthalic anhydride on the surface of the film. Thessi results of this experiment are shown in Table 2 and in Figures 6, 7, and 8. In order to shed some light on this question, films of’ Resin A were placed in the irradiation cell but were shielded by aluminum foil from the ultraviolet rays. The intensity of this band was only 5 per cent greater than that of the background.

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