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Vulcanization kinetics of natural rubber–organoclay nanocomposites
Author(s) -
LópezManchado M. A.,
Arroyo M.,
Herrero B.,
Biagiotti J.
Publication year - 2003
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.12082
Subject(s) - vulcanization , organoclay , materials science , elastomer , composite material , natural rubber , differential scanning calorimetry , nanocomposite , activation energy , kinetics , polymer chemistry , chemistry , organic chemistry , thermodynamics , physics , quantum mechanics
The effect of the incorporation of a bentonite on the vulcanization kinetics of natural rubber was investigated by means of both cure‐meter testing and differential scanning calorimetry (DSC) under dynamic and isothermal conditions. The vulcanization curves showed that the modified clay behaved as an effective vulcanizing agent, accelerating the vulcanization reaction of the elastomer. A marked decrease in the induction time and optimum cure time of the elastomer were observed in the presence of the organoclay. Although the octadecylamine itself accelerated the vulcanization process, the octadecylamine‐modified clay gave rise to a further noticeable increase in the vulcanization rate, which could be attributed to a synergetic effect between the filler and the amine. Moreover, in the presence of the organoclay, a dramatic increase in the torque value was obtained because of the formation of a higher number of crosslinks, which could be attributed to the confinement of the elastomer chains within the silicate galleries and, consequently, to better interactions between the filler and the rubber. However, no significant changes were observed in the unmodified clay composite. These results were in concordance with those obtained by DSC. In addition, the activation energy of the vulcanization process was also calculated by means of both techniques. A clear decrease in the activation energy was observed when the organoclay was added to the nanocomposite, which indicated that the layered silicate favored the processing of the elastomer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1–15, 2003