Rani, Joseph(OPA (Overseas Publishers Association) N.V., July 23, 1997)
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Abstract:
Selected grades of low density polyethylene (LDPE) polystyrene (PS) were extruded in a
laboratory extruder by varying the feeding rate at different revolutions per minute and
temperatures. The mechanical properties of the extruded plastic sheets were determined.
LDPE shows a marked variation in mechanical properties with feeding rate while PS
shows a marginal change in mechanical properties with feeding rate. However, for both
plastics there is a particular feeding rate in the starved region which results in maximum
mechanical properties.
Rani, Joseph(John Wiley & Sons, Inc., October 22, 1997)
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Abstract:
Rubber solutions were prepared and used for bonding wood pieces. The
effect of the variation of chlorinated natural rubber (CNR) and phenolformaldehyde
(PF) resin in the adhesive solutions on lap shear strength was determined. Natural
rubber and neoprene-based adhesive solutions were compared for their lap shear
strength. The storage stability of the adhesive prepared was determined. The change
in lap shear strength before and after being placed in cold water, hot water, acid,
and alkali was tested. The bonding character of these adhesives was compared with
different commercially available solution adhesives. The room-temperature aging
resistance of wood joints was also determined. In all the studies, the adhesive prepared
in the laboratory was found to be superior compared to the commercial adhesives.
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.
The rheological behavior of a short-polyester-fiber-filled polyurethane
elastomer composite containing different bonding agents
has been studied in the temperature range 120-160°C and in the
shear rate range 63-608 s-'. The composite with and without
bonding agents showed a pseudoplastic behavior which decreased
with the increase of temperature. Composites containing bonding
agents based on polypropyleneglycol and 4,4'-diphenylmethanediisocyanate
showed the lowest viscosity values at a particular
shear rate, whereas composites containing a glycerol- (GL) based
bonding agent showed the highest viscosity. The viscosity of the
composite decreased sharply after a particular temperature (140°C) and the fall was less drastic in the composite containing
a GL-based bonding agent.
Sunil,K Narayanankutty(Technomic Publishing Co., Inc., April , 1998)
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Abstract:
The stress relaxation behavior of polyurethane elastomer and
short polyester fiber filled elastomer composites with and without bonding
agents at different strain levels and strain rates was studied. It was found that
these compounds exhibit a multistage relaxation mechanism and that the rate
of relaxation and cross-over time depend on the strain level and strain rate.
The incorporation of fibers reduced the stage-I relaxation rate and increased
the cross-over time of the gum vulcanisate. A higher rate of relaxation (first
stage) was shown by the composites with longitudinal fiber orientation and
composites with bonding agents.
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.
Rani, Joseph(John Wiley & Sons. Inc, August 20, 1998)
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Abstract:
ABSTRACT: Rubber seed oil was used as a multipurpose ingredient in natural rubber
(NR) and styrene butadiene rubber (SBR) compounds. The study shows that the oil,
when substituted for conventional plasticiser, imparts excellent mechanical properties
to NR and SBR vulcanizates. Further, it also improves aging resistance, reduces cure
time, increases abrasion resistance and flex resistance, and reduces blooming.
Rani, Joseph(John Wiley & Sons, Inc., February 16, 1999)
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Abstract:
Microcellular (MC) soles based on polybutadiene (BR) and low-density
polyethylene (LDPE) blends for low-temperature applications were developed. A part of
BR in BR-LDPE blend was replaced by natural rubber (NR) for property improvement.
The BR-NR-LDPE blend-based MC sole shows good technical properties. Sulphur
curing and DCP curing were tried in BR-LDPE and NR-BR-LDPE blends. Study
shows that sulphur-cured MC sheets possess better technical properties than DCPcured
MC sheets. 90/10 BR-LDPE and 60/30/10 BR-NR-LDPE blend combinations are
found to be suitable for low-temperature applications.
Rani, Joseph(John Wiley & Sons, Inc., March 20, 2000)
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Abstract:
ABSTRACT: Zinc salts of ethyl, isopropyl, and butyl xanthates were prepared in the
laboratory. They were purified by reprecipitation and were characterized by IR, NMR,
and thermogravimetric analysis techniques. The melting points were also determined.
The rubber compounds with different xanthate accelerators were cured at temperatures
from 30 to 150°C. The sheets were molded and properties such as tensile strength,
tear strength, crosslink density, elongation at break, and modulus at 300% elongation
were evaluated. The properties showed that all three xanthate accelerators are effective
for room temperature curing.
Rani, Joseph(John Wiley & Sons, Inc., November 1, 2000)
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Abstract:
ABSTRACT: p-Phenylenediamine was chemically attached to low molecular weight chlorinated
paraffin wax. The polymer-bound p-phenylenediamine was characterized by
vapor-phase osmometry (VPO), proton magnetic resonance spectroscopy ('H-NMR),
infrared spectroscopy (IR), and thermogravimetric analysis (TGA). The efficiency and
permanence of the polymer-bound p-phenylenediamine as an antioxidant was compared
with a conventional amine-type antioxidant in natural rubber vulcanizates. The
vulcanizates showed improved aging resistance in comparison to vulcanizates containing
a conventional antioxidant. The presence of liquid polymer-bound p-phenylenediamine
also reduces the amount of the plasticizer required for compounding.
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
Sunil,K Narayanankutty(Taylor & Francis, November 13, 2000)
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Abstract:
Cure characteristics and mechanical properties of short nylon fiber reinforced
acrylonitrile butadiene rubber-reclaimed rubber composites were studied. Minimum
torque, (maximum-minimum) torque and cure rate increased with fiber
concentration. Scorch time and cure time decreased by the addition of fibers.
Properties like tensile strength, tear strength, elongation at break, abrasion loss
and heat build up were studied in both orientations of fibers. Tensile and tear
properties were enhanced by the addition of fibers and were higher in the longitudinal
direction. Heat build up increased with fiber concentration and were
higher in the longitudinal direction. Abrasion resistance was improved in presence
of short fibers and was higher in the longitudinal direction. Resilience increased
on the introduction of fibers. Compression set was higher for blends.
Dielectric properties of polyaniline at different frequencies were studied. Cavity perturbation technique was employed for the
study. Poly aniline in the powder and pelletised forms were prepared under different environmental conditions. Different samples of
poly aniline exhibit high conductivity. However, the conductivity of samples prepared under different environmental conditions is
found to vary. All the samples in the powder form have high conductivity irrespective of the method of preparation. The high
conductivity at microwave frequency makes it possible to be used for developing microwave components like filters.
Sunil,K Narayanankutty(Taylor & Francis Inc., March 26, 2001)
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Abstract:
Cure characteristics and mechanical properties of styrene butadiene rubber
reclaimed rubber blends were studied. The blends showed improved processability,
as indicated by the minimum torque values. Cure characteristics like minimum
torque, (maximum-minimum) torque, cure time and cure rate decreased in the
presence of reclaimed rubber. Tensile strength, tear strength, elongation at break
were higher for blends. Resilience decreased with reclaim content. Compression set
and abrasion loss were higher in the blends.
Rani, Joseph(John Wiley & Sons, Inc., June 21, 2001)
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Abstract:
ABSTRACT: Polyaniline was synthesized by using ammonium persulfate initiator in the
presence of 1M HC1. It was dried under different drying conditions like room temperature
drying (for 48 h), oven drying (at 50-60°C for 8 h under a vacuum), and vacuum
drying (at room temperature for 16 h). The conductivities of these samples were
measured at microwave frequencies. These samples were also pelletized and the
measurements were repeated. The cavity perturbation technique was used for the
study.
Sunil,K Narayanankutty(John Wiley & Sons. Inc., June 21, 2001)
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Abstract:
The effect of diphenylmethane diisocyanate
(MDI) -polyethyleneglycol (PEG) resin on the cure characteristics and mechanical
properties of nitrile rubber/whole tyre eclaim-short nylon fiber
composite-was studied. At a constant loading of 5 phr, the resin composition
was varied. The minimum torque .,id (maximum - minimum) torque increased
with isocyanate concentration. Scorch time and cure time showed a reduction on
introduction of bonding agent. Properties like tensile strength, tear strength, and
abrasion resistance increased with increase in MDI/PEG ratio, and these
properties are higher in the longitudinal direction of fiber orientation.
Compression set increased with isocyanate concentration and the resilience
remain unchanged.
A novel method of blending natural rubber with polyvinylchloride in the latex
stage was developed, Dioctyl phthalate (DOP) and Amine terminated natural rubber
(ATNR) were used as plasticisers, for improving the mechanical properties of
these blends. Properties of the latex stage blends were compared with those of
dry blends. Latex stage blends showed superior mechanical properties compared
to the blends prepared in the dry state. The ageing resistance, oil resistance and
processability were found to be improved by latex stage blending.
Rani, Joseph(Optical Society of America, October 29, 2001)
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Abstract:
A new polymer matrix sensitized with methylene blue for use as an optical recording material is described
here. The characterization is done to determine the optimal recording conditions. These films need no
chemical development and are found to be stable for several months. The matrix has excellent shelf life
and needs an exposure only as short as 20 s. Direct imaging was done on this material.
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)
Fully burnt rice hull (rice hull ash) was tried as a low cost filler in place of precipitated
silica in NBR/PVC based microcellular soles. The mechanical properties of the soles
containing silica and ash are found to be comparable. The expansion is marginally
higher in the presence of ash, which permits to reduce the amount of blowing agent. Cell
structure of microcellular sheets remains unchanged when silica is replaced by ash.