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Thermal degradation of polytetrafluoroethylene in a closed system. Effect of the nature of the surface of the reaction vessel wall
Author(s) -
Jellinek H. H. G.,
Kachi H.
Publication year - 1965
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760050320
Subject(s) - polytetrafluoroethylene , disproportionation , materials science , fluoride , monomer , kinetics , degradation (telecommunications) , thermal , polymer chemistry , composite material , chemical engineering , catalysis , chemistry , thermodynamics , inorganic chemistry , polymer , organic chemistry , telecommunications , physics , quantum mechanics , computer science , engineering
The thermal degradation of polytetrafluoroethylene has been investigated in a closed system as a function of the nature of the surface of the reaction vessel wall. Reproducible results cannot be obtained in a stainless steel vessel as metal fluoride is continuously formed and a stable fluoride is not formed on the wall. Quartz spoon reaction vessels coated with calcium fluoride give a few reproducible runs, before the coating has to be renewed. If the dimerization of the monomer, which takes place very rapidly around 600°C, is considered, first order rates are obtained up to about 75% monomer formation. The kinetics is briefly discussed on the basis of random initiation followed by depropagation with a relatively short kinetic chain length and disproportionation as termination reaction.