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The kinetics of the cyclodehydration reaction of polyhydrazides
Author(s) -
Gebben B.,
Mulder M. H. V.,
Smolders C. A.
Publication year - 1988
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19880200109
Subject(s) - isothermal process , kinetics , materials science , polymer , glass transition , thermodynamics , polymer chemistry , kinetic energy , chemical engineering , composite material , physics , quantum mechanics , engineering
The kinetics of the thermal cyclodehydration reaction of poly‐(1, 3‐phenyl‐1, 4‐phenyl)‐hydrazide a) to poly‐(1, 3‐phenyl‐1, 4‐phenyl)‐oxadiazole b) have been studied by thermo‐gravimetrical analyses. Both an isothermal method and the non‐isothermal Ozawa method have been used to evaluate the kinetic parameters. The kinetics seem to depend upon the physical state of the polymer i.e. the rubbery or glassy state. During isothermal conversions at elevated temperatures the polymer is expected to be initially in its rubbery state followed by a rubber‐glass transition showing a considerable transition in the observed kinetics. The results obtained from the non‐isothermal Ozawa method and the isothermal method agreed well for the polymer in its glassy state. With the non‐isothermal method the process can be followed as a function of the degree of conversion. In this way a parallel reaction could be observed which starts at the end of the conversion process. The morphological state or the history of the polymer seems to have a considerable influence on the kinetics. The film form of the polymer shows a much higher conversion rate than the powder form.