ISSN:
0022-3832
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The differences in thermal decomposition behavior previously observed between linear and branched polyethylenes have been explored experimentally by investigating and comparing the rates of volatilization of a series of twenty polymers. Similar differences were observed between linear and branched polypropylenes. The linear material in both cases exhibited behavior characteristic of a random decomposition, while the branched material did not. Other materials studied included high pressure polyethylene; low pressure copolymers of ethylene with propene, butene, and pentene-1; and polymers and copolymers prepared from diazoalkanes. Systematic deviations from random theory were found to occur with branching. The greater the branching, provided that the branches were longer than one carbon atom, the greater was the rate of decomposition and the more it was at variance with random theory. No quantitative theory accounting for these results is yet available. However, it seems that polymer branching enhances intramolecular transfer at the expense of intermolecular transfer. This is evidenced by the observed rate-conversion curves, which are of a type similar to that found for polymers that decompose mainly into monomer.
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1960.1204414404
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