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Mechanism of radiation vulcanization of natural rubber latex sensitized by monoacrylates
Author(s) -
Hill D. J. T.,
O'Donnell J. H.,
Perera M. C. S.,
Pomery P. J.,
Smetsers P.
Publication year - 1995
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.1995.070571002
Subject(s) - vulcanization , acrylate , natural rubber , polymer chemistry , radical , peroxide , electron paramagnetic resonance , allylic rearrangement , ethyl acrylate , monomer , materials science , photochemistry , chemistry , polymer , organic chemistry , nuclear magnetic resonance , physics , catalysis
The mechanism of radiation vulcanization of natural rubber with 2‐ethyl hexyl acrylate (2EHA) monomer was investigated using electron spin resonance spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The primary radicals formed in the arcylate molecule were found to abstract the allylic hydrogens of the polyisoprene. Crossliking may occur through the allylic radicals and/or main chain radicals formed on the polyacrylate. Acrylate was found to concentrate in the rigid regions of the crosslinked rubber indicating heterogeneity and a nonuniform distribution of the acrylate in the latex particles. The addition of the acrylate and the irradiation seems to effect the Brownian motion of the latex particles. Both the viscosity and the NMR peak widths are effected by the irradiation. Addition of 5% 2EHA increases the crosslinking by a factor of 3.6. The thermal stability of the rubber first increases with the dose in the presence of acrylate, but drops at higher doses due to peroxide formation. © 1995 John Wiley & Sons, Inc.