Sunil,K Narayanankutty(Technomic Publishing Co., Inc., June 1, 1992)
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Abstract:
The flammability of short Kevlar aramide fiber-thermoplastic
polyurethane (TPU) has been investigated with respect to fiber loading and
various flame retardant additives such as halogen containing polymers, antimony
oxide/chlorine donor combination, zinc borate, and aluminum hydroxide.
Smoke generation was reduced drastically, while the oxygen index was reduced
marginally in the presence of short fibers. The best improvement in the oxygen
index was obtained with antimony oxide/chlorinated paraffin wax combination,
in the weight ratio 1:6. A 70 phr loading of aluminum hydroxide improved LOI
and reduced smoke generation.
Sunil,K Narayanankutty(Rapra Technology, August 29, 2006)
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Abstract:
Mechanical properties and thermal degradation of natural rubber compounds
containing castor oil were studied to evaluate its suitability as plasticizer.
Naphthenic oil was used as a reference plasticizer. The cure time was marginally
lower in the case of castor oil mixes, probably due to the presence offree fatty acids
in it. The tear strength and modulus were better in the case of mixes containing
castor oil, while most of the other mechanical properties were comparable to
the mixes containing naphthenic oil. The heat build up and compression set were
higher than that of the naphthenic oil mixes. Thermal studies showed an increase
of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in
the temperature at which the peak rate of degradation occurred. The peak rate
of degradation was comparable to that of the reference compound
Mechanical properties and thermal degradation characteristics of natural rubber compounds
captaining coconut oil were compared with that of a control compound containing naphthenic oil.
Cure time was marginally lower in the case of coconut oil mixes, probably due to the presence of
free fatty acids. Tensile strength , tear strength, resilience and abrasion resistance were better than
the naphthenic oil-based compounds . Compression set and hardness were marginally inferior
The coconut oil mixes had a crosslink density comparable to that of the reference compound.
Thermal studies showed that the temperature of initiation of degradation was increased by 10°C
and the temperature at which the peak rate of degradation occured was increased by 7°C. The
peak rate of degradation was compa rable to the control compound.
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.
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.
Sunil,K Narayanankutty(Taylor & Francis Inc., October 28, 2004)
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Abstract:
The thermal properties of short Nylon-6 fiber-reinforced Styrene butadiene rubber
(SBR) composites were studied by Thermogravimetric Analysis (TGA). The effect
of epoxy-based bonding agent on thermal degradation of the gum and the composites
was also studied. The thermal stability of the SBR was enhanced in the presence
of Nylon-6 fibers and the stability of the composites increased in the presence
of bonding agent. The epoxy resin did not significantly change the thermal stability
of SBR gum vulcanizate. Results of kinetic studies showed that the degradation
of SBR and the short nylon fiber-reinforced composites with and without
bonding agents followed first-order kinetics.
Sunil,K Narayanankutty(Elsevier Science Limited, May 17, 1997)
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Abstract:
The thermal degradation of short polyester fiber reinforced polyurethane composites
with and without different bonding agents has been studied by thermogravimetric
analysis . It was found that degradation of the polyurethane takes
place in two steps and that of the composites takes place in three steps. With
the incorporation of 30 phr of fiber in the matrix , the onset of degradation was
shifted from 230 to 238 ° C. The presence of bonding agents in the virgin elastomer
and the composite gave an improved thermal stability . Results of kinetic studies
showed that the degradation of polyurethane and the reinforced composites with
and without bonding agents follows first -order reaction kinetics