ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The degradation of phenol-formaldehyde polycondensates has been investigated by mass spectrometric thermal analysis to 800°C. The thermal oxidative mechanism proposed by Conley and co-workers has been confirmed. Direct analysis of products at frequent intervals of a temperature-programmed heating cycle demonstrates the existence of postcuring, general degradation, and char-forming stages. Activation energies for formation of each product and for degradation of the polymer have been determined. Phenolic homologs, products of thermal scission of methylene-phenyl bonds, show high activation energies; oxidation products have activation energies comparable to or slightly higher than that for oxidation of methylene bridges to carbonyl groups. The tarry high molecular weight products found on pyrolysis at atmospheric pressure are not formed in high vacuum because recombination reactions of phenols and formaldehyde are minimized. Otherwise, no major change in product composition, as compared to the high heating rate pyrolysis-gas chromatographic investigation of Jackson and Conley, was observed.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1966.070100407
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