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Abstract:
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The thesis describes utilisation of reclaimed rubber, Whole Tyre
Reclaim (WTR) produced from bio non- degradable solid pollutant scrap
and used tyres. In this study an attempt has made to optimize the
substitution of virgin rubber with WTR in both natural and synthetic rubber
compounds without seriously compromising the important mechanical
properties. The WTR is used as potent source of rubber hydrocarbon and
carbon black filler. Apart from natural rubber (NR), Butadiene rubber (BR),
Styrene butadiene rubber (SBR), Acrylonitrile butadiene rubber (NBR) and
Chloroprene rubber (CR) were selected for study, being the most widely
used general purpose and specialty rubbers. The compatibility problem was
addressed by functionalisation of WTR with maleic anhydride and by using
a coupling agent Si69.The blends were systematically evaluated with respect
to various mechanical properties. The thermogravimetric analyses were
also carried out to evaluate the thermal stability of the blends.Mechanical properties of the blends were property and matrix
dependant. Presence of reinforcing carbon black filler and curatives in the
reclaimed rubber improved the mechanical properties with the exception of
some of the elastic properties like heat build up, resilience, compression set.
When WTR was blended with natural rubber and synthetic rubbers, as the
concentration of the low molecular weight, depolymerised WfR was
increased above 46-weight percent, the properties deteriorates.When WTR was blended with crystallizing rubbers such as natural
rubber and chloroprene rubber, properties like tensile strength, ultimate
elongation were decreased in presence of WTR. Where as in the case of blends of WTR with non-crystallizing rubbers reinforcement effect was
more prominent.The effect of functionalisation and coupling agent was studied in
three matrices having different levels of polarity(NBR, CR and SBR).The
grafting of maleic anhydride on to WTR definitely improved the properties
of its blends with NBR, CR and SBR, the effect being prominent in
Chloroprene rubber.Improvement in properties of these blends could also achieved by
using a coupling agent Si69. With this there is apparent plasticizing effect at
higher loading of the coupling agent. The optimum concentration of Si69
was 1 phr for improved properties, though the improvements are not as
significant as in the case of maleic anhydride grafting.Thermal stability of the blend was increased by using silane-coupling
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