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A comparison of the physical properties of radiation and sulfur‐cured poly(butadiene–co–styrene)
Author(s) -
Böhm G. G. A.,
Detrano M.,
Pearson D. S.,
Carter D. R.
Publication year - 1977
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.1977.070211202
Subject(s) - curing (chemistry) , materials science , carbon black , composite material , sulfur , radiation , glass transition , swelling , styrene butadiene , irradiation , natural rubber , styrene , polymer chemistry , polymer , copolymer , physics , nuclear physics , metallurgy , quantum mechanics
The physical properties of radiation‐ and sulfur‐cured poly(butadiene–co–styrene)‐based stocks were compared. It was found that the measured lower ultimate strength of radiation‐cured stocks is in part attributable to the difference in the glass transition temperatures of the stocks cured by the two methods (an increase in T g is caused by sulfur curing). Another factor contributing to the difference in performance is the apparent nonuniform crosslink density distribution in radiationcured stocks containing carbon black filler. A higher crosslink density in the immediate vicinity of carbon black particles was postulated based on a to‐be‐expected distribution of secondary electron energy at interfaces with an appreciable change in density between neighboring phases. The invoked difference in network topology, supported by solvent swelling measurements on sulfur‐ and radiation‐crosslinked vulcanizates can explain not only the slightly lower ultimate strength of radiation‐cured stocks but also the superior fatigue and crack propagation performance measured for these culcanizates. Finally, theoretical arguments were presented to explain the inferred large strength deficiency of radiation‐cured rubbers reported by other investigators on the basis of chain scissions encountered during radiation crosslinking.