Rani, Joseph(HUthig & Wepf Verlag Basel, December 12, 1986)
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Abstract:
Blends of polychloroprene rubber and plasticized polyvinylchloride have been prepared
in various compositions and their properties evaluated. The properties of the
blends show that they can be used to replace polychloroprene in many applications
Anantharaman, M R; Mathew, George; Philip, Kurian(Wiley Subscription Services, Inc., A Wiley Company, September 22, 2010)
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Abstract:
Ultra fine nickel ferrite have been synthesized
by the sol-gel method. By heat treating different portions
of the prepared powder separately at different
temperatures, nano-sized particles of nickel ferrite with
varying particle sizes were obtained. These powders were
characterised by the X-ray diffraction and then incorporated
in the nitrile rubber matrix according to a specific
recipe for various loadings. The cure characteristics and
the mechanical properties of these rubber ferrite composites
(RFCs) were evaluated. The effect of loading and the
grain size of the filler on the cure characteristics and tensile
properties were also evaluated. It is found that the
grain size and porosity of the filler plays a vital role in
determining the mechanical properties of the RFCs
Anantharaman, M R; Soloman, M A; Philip, Kurian; Joy, P A(Wiley Periodicals, September 26, 2002)
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Abstract:
Fine particles of barium ferrite (BaFe12O19)
were synthesized by the conventional ceramic technique.
These materials were then characterized by the X-ray diffraction
method and incorporated in the natural rubber matrix
according to a specific receipe for various loadings of
ferrite. The rubber ferrite composites (RFC) thus obtained
have several applications, and have the advantage of molding
into complex shapes. For applications such as microwave
absorbers, these composites should have an appropriate
dielectric strength with the required mechanical and
magnetic properties. The N330 (HAF) carbon black has been
added to these RFCs for various loadings to modify the
dielectric and mechanical properties. In this article we report
the effect of carbon black on the mechanical and dielectric
properties of these RFCs. Both the mechanical and dielectric
properties can be enhanced by the addition of an appropriate
amount of carbon black
Description:
Journal of Applied Polymer Science, Vol. 89, 769–778 (2003)
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.
Rani, Joseph(Wiley InterScience, December 13, 2004)
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Abstract:
Prevulcanized natural rubber latex was prepared
by the heating of the latex compound at 55°C for
different periods of time (2, 4, 6, 8, and 10 h). The changes in
the colloidal stability and physical properties were evaluated
during the course of prevulcanization. The prevulcanized
latex compounds were stored for 300 days, and the
properties were monitored at different storage intervals (0,
20, 40, 60, 120, 180, 240, and 300 days). During prevulcanization,
the mechanical stability time increased, and the viscosity
remained almost constant. The tensile strength increased
during storage for a period of 20 days. The degree of
crosslinking, modulus, elongation at break, and chloroform
number were varied with the time of storage.
Chandrasekaran, M; Jissa, Krishna G; Ansu, Jacob; Elyas, K K; Philip, Kurian(Academic Press, April 24, 2013)
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Abstract:
Prodigiosin is known for its immunomodulatory, antibacterial, antimycotic, antimalarial, algicidal and anticancer activities. Here, we reported the evaluation of prodigiosin pigment as a dyeing agent in rubber latex, paper and polymethyl methacrylate (PMMA) so that it can be considered as an alternative to synthetic pigments. Maximum color shade was obtained in rubber sheet prepared with 0.5 parts per hundred gram of rubber (phr) pigment and PMMA sheet incorporated with 0.08 μg pigment. Results indicate scope for utilization of prodigiosin as dye for PMMA and rubber and also prodigiosin dyed paper as a pH indicator. Further, being a natural and water insoluble pigment, it is ecofriendly
Description:
African Journal of Biotechnology Vol. 12(17), pp. 2266-2269, 24 April, 2013
A series of short-isora-fiber-reinforced natural
rubber composites were prepared by the incorporation of
fibers of different lengths (6, 10, and 14 mm) at 15 phr loading
and at different concentrations (10, 20, 30, and 40 phr) with a
10 mm fiber length. Mixes were also prepared with 10 mm
long fibers treated with a 5% NaOH solution. The vulcanization
parameters, processability, and stress-strain properties
of these composites were analyzed. Properties such as tensile
strength, tear strength, and tensile modulus were found to be
at maximum for composites containing longitudinally oriented
fibers 10 mm in length. Mixes containing fiber loadings of 30 phr with bonding agent (resorcinol-formaldehyde [RF]
resin) showed mechanical properties superior to all other
composites. Scanning electron microscopy (SEM) studies
were carried out to investigate the fiber surface morphology,
fiber pullout, and fiber-rubber interface. SEM studies showed
that the bonding between the fiber and rubber was improved
with treated fibers and with the use of bonding agent.
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.
Sunil,K Narayanankutty(Elsevier Science Publishers Ltd., August 29, 1991)
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Abstract:
The thermal degradation of short kevlar fibre-thermoplastic polyurethane
(TPU) composites has been studied by Thermogravimetric Analysis (TGA)
and Differential Scanning Calorimetry (DSC). TGA showed that the thermal
degradation of TPU takes place in two steps with peak maxima (T1max and
T2ma,) at 383°C and 448°C, respectively. In the presence of 10-40 phr of short
kevlar fibres, T1_ and T2max were shifted to lower temperatures. The
temperature of onset of degradation was increased from 245 to 255°C at 40
parts per hundred rubber (phr) fibre loading. Kinetic studies showed that the
degradation of TPU and kevlar-TPU composite follows first-order reaction
kinetics. The DSC study showed that there is an improvement in thermal
stability of TPU in the presence of 20 phr of short kevlar fibres.
Rani, Joseph(Huthig & Wepf Verlag,Basel, April 16, 1993)
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Abstract:
Scrap latex products contain rubber hydrocarbon of very high quality, that is only
slightly crosslinked. A novel economic technique for converting such latex waste into
a processible material is developed. This paper reports the effect of adding this latex
reclaim to natural rubber. It is shown that latex reclaim can replace raw natural rubber
up to about 50 wt.% without affecting mechanical properties.