Rani, Joseph(Wiley lnterScience, September 4, 2006)
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Abstract:
The latex industry has expanded over the
years to meet the world demands for gloves, condoms,
latex thread etc. Because of the strict specifications for
the products and the unstable nature of the latex, as
high as 15%, of the final latex products are rejected.
Since waste latex rubber (WLR) represents a source of
high quality rubber hydrocarbon, it is a potential candidate
for generating reclaimed rubber of superior quality.
Two types of WLR with different amounts of polysulfidic
bridges are used in these experiments, which are
reclaimed with variation of the concentration of the
reclaiming agents, the reclamation temperature and time,
Di phenyldisultide, 2-aminophenyldisulfide and 2,2'-dibenzamidodiphenyldisulfide
(DBADPDS) are used as reclaiming
agents, and the effect of diphenyldisulfides (DPDS)
with different substituents, on the reclamation efficiency of WLR is investigated. A kinetic study of the reclamation
reaction with the three reclaiming agents is done.
The reaction rates and activation energies are calculated
and compared with literature values. The comparative
study of the three different reclaiming agents shows that
(DBADPDS) is able to break the crosslinks at temperature
levels 20'C below the temperature levels normally
used with DPDS. Another advantage of this reclaiming
agent is the reduced smell during the reclamation process
and of the final reclaims, one of the most important
shortcomings of other disulfides used for this purpose.
Thomas, Kurian; Jacob, Samuel; Thommachan, Xavier(Wiley Periodicals, December , 2001)
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Abstract:
High styrene rubber ionomers were prepared by sulfonating styrene–butadiene
rubber of high styrene content (high styrene rubber) in 1,2-dichloroethane using
acetyl sulfate reagent, followed by neutralization of the precursor acids using methanolic
zinc acetate. The ionomers were characterized using X-ray fluorescence spectroscopy,
Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance
spectroscopy (NMR), dynamic mechanical analysis (DMA), and also by the evaluation
of mechanical properties. The FTIR studies of the ionomer reveal that the sulfonate
groups are attached to the benzene ring. The NMR spectra give credence to this
observation. Results of DMA show an ionic transition (Ti) in addition to glass–rubber
transition (Tg). Incorporation of ionic groups results in improved mechanical properties
as well as retention of properties after three cycles of processing
Description:
Journal of Applied Polymer Science, Vol. 85, 2294–2300 (2002)
Rani, Joseph(Wiley lnterScience, February 12, 2006)
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Abstract:
It is observed that reclamation of natural rubber
latex based rubber using 2,2'-dibenzamidodiphenvldisulphide
as reclaiming agent is an optional methodology for
recycling of waste latex rubber (WLR). For progressive replacement
of virgin natural rubber by the reclaim, two alternatives
curing system were investigated: adjustment or reduction of
the curing system with increasing reclaim content, to compensate
for the extra amount of curatives brought along by the reclaim.
For fixed curing system, as if the reclaim were equivalent
to virgin NR. The cure behavior, final crosslink density
and distribution, mechanical properties, and dynamic
viscoelastic properties of the blends with reclaimed WLR are
measured and compared with the virgin compound. The morphology of the blends, sulfur migration, and final distribution
are analyzed.The mechanical and dynamic viscoelastic
properties deteriorate for both curing systems, but to a lesser
extent for fixed curing system compared to adjusted curing
system. With the fixed cure system, many properties like tensile
strength and compression set do still deteriorate, but tan 6
and Mrrr„/Murxr, representative for the rolling resistance of tires
are improved. On the other hand, with the adjusted cure system
both mechanical and dynamic properties still deteriorate.