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 thermal decomposition of low-density polyethylene, isotactic polypropylene, and polyisobutylene has been studied in helium at a heating rate of 20°C/min using an experimental system which consists of a programmable pyrolyzer, a thermal conductivity cell, and a mass chromatograph.For low-density polyethylene, the formation of a homologous series of volatile products corresponding to alkanes and alkanes is interpreted in terms of an intramolecular radical transfer process in the primary macroradicals to the 5th, 9th, 13th, and 17th carbon atoms of the chain.For isotactic polypropylene, the formation of a homologous series of volatile products corresponding to monomer, dimers, trimers, and higher oligomers is explained also in terms of intramolecular radical transfer processes. Transfers to the 5th, 9th, and 13th carbon atoms in the secondary macroradicals (indexing from the secondary carbon atom at the chain end) and transfers to the 6th, 10th, and 12th carbon atoms in the primary macroradicals are shown to account for the major products of pyrolysis.For polyisobutylene, in addition to the depolymerization process which accounts for the extensive formation of monomer, intramolecular radical transfer processes in the primary and tertiary macroradicals (the processes proceeding predominantly in the primary macroradicals) are shown to account for the formation of the dimers, trimers, and higher oligomers that occur in the volatile products of decomposition.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1976.070200803
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