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Heat stability of chemically crosslinked polyethylene
Author(s) -
Narkis M.,
Tobolsky A. V.
Publication year - 1970
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1970.070140107
Subject(s) - carbon black , materials science , polyethylene , modulus , thermal stability , carbon fibers , polymer , degradation (telecommunications) , stress relaxation , relaxation (psychology) , amorphous solid , composite material , polymer chemistry , chemical engineering , chemistry , organic chemistry , creep , composite number , psychology , telecommunications , social psychology , natural rubber , computer science , engineering
Heat stability in air of chemically crosslinked polyethylene loaded with medium thermal (MT) carbon black was studied as a function of temperature and carbon black content. Weight loss at 200° to 250°C is practically independent of the carbon black concentration. Modulus–temperature curves are changed with various heat treatment periods at 225°C. These curves show that the rubbery modulus (amorphous state) increases with increasing the heating period, while the modulus of the partially crystalline polymer goes through a minimum and then increases. Continuous stress‐relaxation and intermittent stress curves show the existence of degradation and crosslinking reactions, the latter becoming more important at higher temperatures or longer times. The degradation reaction is practically independent of the carbon black content while the crosslinking reaction at 225°C is faster with increasing MT black concentrations. It is concluded that reasonable heat stability, in the crosslinked polyethylene compounds studied, can be obtained at temperatures lower than 150°C.