Jacob, Samuel; Dr.Thomas, Kurian; Dr.George, K E(Cochin University of Science and Technology, December 28, 2002)
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Abstract:
Novel thermo-reversible zinc sulphonated ionomers based on styrene butadiene
rubber (SBR), and high styrene rubber (HSH) were synthesized by sulphonation
followed by neutralization with zinc. The sulphonate content of the ionomer was
estimated by using x-ray fluorescence spectroscopy. Presence of sulphonate groups
has been confirmed by FTIR and FTNMR spectra. The TGA results show improvement
in the thermo~oxidative stability of the modified rubber. Both DSC and DMTA studies
show that the incorporation of the ionic groups affect the glass rubber transition of the
base polymer. lntroduction ol ionic functionality in to the base material improved the
physical properties. Retention of the improved physical properties of the novel
ionomers even after three repeated cycles of mixing and molding may be considered
as the evidence for the reprocessability of the ionomer. Effect of particulate fillers
(HAF black, silica and zinc stearate) on the properties of the zinc sulphonated styrene
butadiene rubber ionomer has been evaluated. Incorporation of tillers results in
improvement in mechanical properties. Zinc stearate plays the dual role of
reinforcement and plasticization. The evaluation of dielectric properties of zinc
sulphonated styrene butadiene rubber iorpmers at microwave frequencies reveal that
the materials show conductivity at semiconductor level. The real and imaginary parts
of the complex permittivity increases with increase in ionic functionality. Use of the
38.5 ZnS-SBR ionomer as a compatibiliser for obtaining the technologically compatible
blends from the immiscible SBR/NBR system has been discussed.
Description:
Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology