CoA. Notes: Materials (1963-1969)
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Browsing CoA. Notes: Materials (1963-1969) by Author "Smith, D. A."
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Item Open Access The effect of curing conditions on the extent of cure of Polyester Resin Crystic 189 (Scot-Bader Ltd.)(College of Aeronautics, 1968-06) Smith, D. A.The cross-linking, or cure, of Scot Bader Polyester Resin Crystic 139 (L.V.) was investigated by examining the resin during cure by means of acetone Soxhlet extractions and Barcol hardness tests. The experiments were designed to test Funke’s hypothesis that in the cure of polyester resins the nature of the final network is predetermined by conditions before the gel Point, and that post-gel conditions affect the rate of cure but not the nature of the final network and the final degree of conversion. Funke’s work was based on analysis of the final products of hydrolytic degradation of polyesters, which is quite different from the methods used in this investigation. It was concluded that the evidence did not support Funke’s hypothesis and explanations are afforded for this and suggestions for future work are recorded.Item Open Access The reaction of perfluoroglutaric acid with methyl magnesium iodide. Part 2(College of Aeronautics, 1968-08) Smith, D. A.Perfluoroglutaric acid when treated with methyl magnesium iodide afforded hexafluoro-2,6-dimethylpyran-2,6-diol in high yield and 2,213,3,4,4-hexafluoro- 5-oxocaproic acid in low yield. The former appeared to exist in a range melting form (61.-79°C) and also in a very labile form melting at 96-98°C. Problems associated with the formation of this latter form were investigated. The hexafluoro-2,6-dimethylpyran-2,6-diol yielded a monosemi-carbazone and also a mono and a di1(2,4-dinitrophenylhydrazone). The mono (2,4-dinitro phenylhydrazone) appeared to be cyclic. Reduction, both with lithium aluminium hydride and sodium borohydride yielded 3,3,4,415,5-hexafluoro-n-heptane-2,6-diol. Reaction with anhydrous calcium sulphate gave 3,3,414,515-hexafluoro-2- methylcyclohex-l-ene-6-one. The acid product of the original reaction of perfluoroglutaric acid and methyl magnesium iodide was characterised as a 2,4-dinitrophenylhydrazone and as an S-benzylthiouronium salt. Infra-red spectroscopic evidence suggests the latter compound exists in a straight chain form.Item Open Access Some aspects of the thermal degradation of epoxide resins. Part 1(College of Aeronautics, 1965-03) Stuart, J. M.; Smith, D. A.This Note contains a review of previous work in the field of pyrolytic degradation of epoxide resins, and a description of the development of an instrument for this purpose, using the principle of gas chromatography. The method depends on the pyrolysis of the material using an electrically heated filament, the difficulties of this method are critically examined, and attempts to overcome them described. The pyrolytic degradation in a nitrogen atmosphere, of unhardened epoxide resin was investigated, likewise the degradation of resin hardened with 1:2 diamino ethane and triethylenetetramine, is described. An attempt has been made to explain, in terms of possible degradation reactions, the actual compounds detected in the pyrolytic break-down.Item Open Access A study of the thermal degradation of an amine-cured epoxide resin at temperatures below 350 degrees C(College of Aeronautics, 1967-01) Patterson-Jones, C.; Smith, D. A.An epoxy resin made by the reaction of the diglycidyl ether of bis-phenol A and diaminodiphenyl methane was thermally degraded in vacuo at temperatures between 200°C and 350°C. The effect of degradation was examined by means of measurement of changes in the dielectric properties of the material and also by examination of compounds evolved by the cured resin. Definite evidence for the evolution of N-methyl aniline and N:N-dimethylaniline is advanced and added evidence for a dehydration reaction is put forward. Possible degradation mechanisms are discussed.