Rani, Joseph(Hitthig & Wepf Verlag, Basel, October 13, 1986)
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Abstract:
A carbon black filled 50/50 natural rubber (NR)/styrene-butadiene rubber (SBR)
blend is vulcanized using several conventional curing systems designed by varying the
amounts of sulphur and accelerator. The cure characteristics and the properties of the
vulcanizates are compared. The quantity and quality of crosslinks in each case are
evaluated by chemical probes to correlate them with the properties.
Sunil,K Narayanankutty(Sage Publications, April , 2002)
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Abstract:
Cure characteristics and mechanical properties of acrylonitrile
butadiene rubber/reclaimed rubber blends were studied. Minimum torque,
(ma)dmum -minimum) torque, scorch time, cure time and cure rate decreased in
presence of reclaimed rul3ber. Tensile strength, elongation at break and
compression set increased'with increase in reclaim content. Resilience and
abrasion resistance decreased with reclaim loading. Heat build up was higher for
the blends. The ageing resistance of the blends was inferior to that of the gum
compound.
Sunil,K Narayanankutty(Sage Publications, April , 2002)
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Abstract:
Acrylonitrile butadiene rubber (NBR) matrix was reinforced with
different levels of short nylon fiber loading. Cure characteristics and mechanical
properties of composites in longitudinal and transverse directions have been
studied. Cure time was reduced while processability, as indicated by the
minimum torque, was marginally reduced with increase in fiber loading. Tensile
and tear properties improved with fiber concentration and the values were
higher in longitudinal direction of fiber orientation. Abrasion resistance,
resilience and compression set were increased in presence of fibers. Elongation
at break values showed a drastic drop on introduction of fibers. Heat build up
was higher for composites.
Rani, Joseph(John Wiley & Sons,Inc., December 29, 1997)
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Abstract:
ABSTRACT: The electrical conductivity of silicone rubber vulcanizates containing carbon
blacks [e.g., acetylene black, lamp black, and ISAF (N-234) black] were investigated.
The change in electrical conductivity with varying amounts of carbon blacks and the
temperature dependence was measured. The mechanical properties like tensile
strength, tear strength, elongation at break, hardness, etc., of the vulcanizates were
determined. A comparative study of the electrical conductivity of the composites revealed
that the electrical conductivity of the composites made with acetylene black was
higher than that of the composites made of other blacks.
Carbon Black is incorporated In natural rubber latex in , the presence of
polyethylene glycol. The dispersion of carbon blade in the vulcanizatea is
analyzed using polaroid M.4 land camera The mechanical properties of the
carbon black meeterbatched NR/SBR blend Is compared with that of conventional
NR/SBR blend before and after ageing , The resilience, flex resistance
and hardness are found to be superior for N-LCMISBR compounds.
The compression set and abrasion resistance are comparable for both types
of blends . The processebiity and die swell of these blends at different shear
rates are also compared.
Blends of Acrylonitrile rubber with Maleic anhydride grafted Whole Tyre
Reclaim WTR (MA-g-WTR) have been prepared and the cure and mechanical
properties have been studied with respect to reclaim content. Control
compounds containing unmodified WTR were also prepared for comparison.
Grafting was confirmed by IR studies. Blends containing grafted WTR showed
higher minimum torque and (max-min) torque. They also showed longer cure
time, scorch time and lower cure rate. Grafting of the WTR with maleic
anhydride also resulted in the improved tensile strength, abrasion resistance,
compression set and resilience. However, the heat build up under dynamic
loading was marginally higher for the blends containing grafted reclaimed
rubber.
Paraphenylenediamine and diphenylamine were chemically
attached to natural rubber during mastication . The rubber bound antioxidants
were characterized by TLC, 'H-NMR, IR and TGA. The efficiency and
permenance of these bound antioxidants were compared with a conventional
amine type antioxidant in filled natural rubber vulcanizates . The rubber
bound antioxidants were found to be less volatile and less extractable as compared
to conventional antioxidants. The vulcanizates showed improved ageing
resistance as compared to vulcanizates containing conventional antioxidants.
This semisolid rubber bound antioxidant can reduce the amount of plasticizer
required for compounding.
Rani, Joseph(Elsevier Science Limited, July 3, 1994)
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Abstract:
Diphenylamine was chemically attached to depolymerised natural rubber by
photochemical reaction. The rubber-bound diphenylamine was characterised
by TLC, HNMR, IR and TGA. The efficiency and permanence of the bound
diphenylamine was compared with conventional amine type antioxidant in
natural rubber vulcanizates. The rubber-bound diphenylamine was found to be
less volatile and less extractable compared to the conventional antioxidant.
The vulcanizates showed improved ageing resistance in comparison to vulcanizates
containing conventional antioxidant . Also, the presence of liquid
rubber-bound diphenylamine reduces the amount of plasticiser required for
compounding.
Para-phenylenediamine (PD) was chemically attached to depolymerized natural rubber by
a photochemical reaction . The rubber bound PD was characterized by TLC, 1H-NMR, IR,
and TGA. The efficiency and permanence of the bound PD were compared with conventional
antioxidants in NBR vulcanizates . The rubber bound PD was found to be less volatile and
more resistant to water and oil extraction . The vulcanizates showed improved aging resistance
in comparison to vulcanizates containing conventional antioxidants. The liquid rubber
bound antioxidant reduces the amount of plasticizer required for compounding
Studies conducted on butadiene-acrylonitrile copolymer (NBR)/poly(vinyl chloride) (PVC)
blends at different temperatures indicate that an optimum temperature exists for the formation
of a particular blend. The mechanical properties of the blends confirm this observation.
PVC stabilizer based on, magnesium oxide , zinc oxide, and stearic acid was found to be very
useful in NBR/PVC blends.
Rani, Joseph(Huthig & Wepf Verlag, Basel, June 5, 1991)
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Abstract:
Antioxidants were attached to hydroxy-terminated liquid natural rubber by modified
Friedel-Crafts alkylation reaction using anhydrous zinc chloride as catalyst. The rubber
bound antioxidants were found to be less volatile and less extractable compared to
conventional antioxidants. The bound antioxidants were tried both in latex compounds
and dry rubber compounds. The vulcanizates showed improved ageing resistance
compared to vulcanizates based on conventional antioxidants.
Rani, Joseph(John Wiley & Sons,Inc., July 31, 1998)
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Abstract:
ABSTRACT: Nylon tire cord (1680/2) was dipped in different adhesives based on resorcinol
formaldehyde resin and latex (RFL) and was bonded to natural rubber-based
compounds. The resin-rubber ratio in the RFL adhesive was optimized. The variation
of pull-through load was studied by varying the drying and curing temperature of the
dipped nylon tire cord. RFL adhesive based on vinylpyridine latex was found to have
better rubber-to-nylon tire cord bonding, compared with the one based on natural
rubber latex. Addition of a formaldehyde donor into the RFL adhesive/rubber compound
improves adhesion.
In natural rubber/high styrene resin microcellular sheets, part of
natural rubber was replaced by latex reclaim prepared from waste
latex products. The mechanical properties and cell structure of
the products were evaluated. It was found that latex reclaim can
replace about 30% of natural rubber without affecting the technical
properties of the microcellular sheets.
Rani, Joseph(Gordon and Breach Science Publishers, Inc., November 13, 1986)
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Abstract:
A carbon black filled 50/50 Natural Rubber (NR)/Polybutadiene Rubber (BR) blend
is vulcanized using several conventional systems designed by varying the amounts of
sulphur and accelerator . The cure characteristics and the vulcanizate properties are
compared. The quality and quantity of crosslinks in each case are deciphered by
chemical probes to correlate them with the vulcanizate properties.
Blends of 50/50 natural rubber (NR) and styrene-butadiene rubber (SBR) are vulcanized using
several conventional and semi-EV systems. The cure characteristics and vulcanizate properties
are compared. The quantity and quality of crosslinks in each case are deciphered by chemical
probes to correlate them with the vulcanizate properties.
Rani, Joseph(Gordon and Breach Science Publishers, Inc., August 30, 1985)
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Abstract:
Blends of natural rubber (NR) with styrene-butadiene rubber (SBR), polybutadiene
rubber (BR), ethylene-propylene terpolymer (EPDM) and acrylonitrile-butadiene
rubber (NBR) were vulcanised using an efficient vulcanisation (EV) system and a
semi-EV system. Compatible blends show a definite pattern of curing whereas the
incompatible blends show no such pattern.
The cure characteristics of short fiber-polyurethane elastomer
were studied with respect to different fiber-matrix bonding agents. A hexamethylenetetramine-
resorcinol -hydrated silica based bonding agent was found to affect
the stability of the composite. A new bonding agent, TP resin, based on polymeric
toluenediisocyanate and polypropylene glycol has been developed. Cure characteristics
of the composite with and without TP resin at different fiber loadings were
also compared. Minimum torque, scorch time and optimum cure time increased
with fiber content. Maximum torque was consistently higher with TP resin at all
fiber loadings.
Rani, Joseph(Wiley Inter Science, December 14, 2005)
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Abstract:
Polypyrrole/poly (vinyl chloride) semi-interpenenzrtirtg
networks of different compositions are prepared using anunonitun per
sulfate initiator at room temperature in pellet.form and lilrrt form and
their dielectric properties are studied at different microwave frequencies.
An HP 8510 Vector network analyzer interfaced with a computer
is used. The cavity-perturbation technique is employed for the
study
Rani, Joseph(Wiley Periodicals, Inc., October 23, 2003)
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Abstract:
Poly(o-toluidine) (PoT) and poly(o-toluidine
co aniline) were prepared by using ammonium persulfate
initiator, in the presence of 1M HCI. It was dried under
different conditions: room temperature drying (48 h), oven
drying (at 50°C for 12 h), or vacuum drying (under vacuum,
at room temperature for 16 h). The dielectric properties, such
as dielectric loss, conductivity, dielectric constant, dielectric
heating coefficient, loss tangent, etc., were studied at microwave frequencies. A cavity perturbation technique was used
for the study. The dielectric properties were found to be
related to the frequency and drying conditions. Also, the
copolymer showed better properties compared to PoT alone.
Rani, Joseph(John Wiley & Sons, Inc., November 8, 2000)
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Abstract:
ABSTRACT: The dipping characteristics of radiation-vulcanized natural rubber latex
and natural rubber latex compounds were investigated with a lab-model semiautomatic
dipping machine. The effect of the variation of the speed of immersion and withdrawal,
dwell time, compound viscosity, and concentration of coagulant on the thickness of the
latex deposit was investigated. The results of the study show that the deposit thickness
depends on the withdrawal speed of the former, the concentration of the coagulant,
dwell times, and the viscosity of the latex compounds