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Estimation of butadiene in vulcanized BR and SBR by thermographic analysis
Author(s) -
Sircar A. K.,
Lamond T. G.
Publication year - 1973
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.1973.070170822
Subject(s) - vulcanization , polybutadiene , arrhenius plot , exothermic reaction , styrene butadiene , natural rubber , activation energy , differential scanning calorimetry , materials science , arrhenius equation , polymer , polymer chemistry , composite material , styrene , chemistry , thermodynamics , organic chemistry , copolymer , physics
A method for the determination of butadiene in vulcanized polybutadiene (BR) and styrene–butadiene rubber (SBR) has been proposed. The method is based on determining the area under the exothermic peak (around 380°C) of the differential scanning calorimetry thermograph in nitrogen. The exotherm area was found to be linearly related to the butadiene content of the polymers and was unaffected by vulcanization or by loading with carbon black. This approach supplements and extends the existing methods of BR determination, which depend upon the estimation of styrene content. The existing evidence indicates that the exothermic reaction is due to cyclization of BR. The energy of activation calculated from the Arrhenius plot is 32–35 kcal/mole; it does not change with vulcanization, loading, or nature of the polymer.