Seema, A; Dr.Narayanankutty,Sunil K(Cochin University of Science & Technology, September , 2004)
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Abstract:
The thesis describes the development and evaluation of epoxy
resin as interfacial bonding agent for short Nylon-6 fiber elastomer
composites. Epoxy resin is well known for its adhesive property. The
potential use of it as interfacial bonding agent in short fiber composite is
not explored yet. Three rubbers viz., acrylonitrile butadiene rubber
(NBR), Neoprene rubber (CR) and styrene butadiene rubber (SBR) were
selected and different fiber loading were tried. The resin concentration
was optimized for each fiber loading with respect to cure characteristics
and mechanical properties. Rheological characteristics and thermal
degradation of the composites containing different fiber loading and
different resin concentrations were studied in detail to find the effect of
epoxy resin bonding system. The mechanical properties were studied in
detail. The short Nylon -6 fiber improved most of the mechanical
properties of all the three rubbers. Tensile strength showed a dip at 10
phr fiber loading in the case of CR while it was continuously increased
with fiber loading in the case of NBR and SBR. All the composites
showed anisotropy in mechanical properties. The epoxy resin is an
effective bonding agent for short Nylon -6 fiber reinforced NBR and CR
composites. Epoxy resin improved tensile strength, abrasion resistance
and modulus of these composites. SEM studies confirmed the improved
bonding of fiber and matrix in the presence of epoxy bonding agent.
Epoxy resin was not effective as bonding agent in the case of short Nylon
fiber- SBR composite. From the rheological studies of the composites
with and without bonding agent it was observed that all the composite
exhibited pseudoplasticity, which decreased with temperature. At higher
shear rates all the mixes showed plug flow. SEM pictures showed that
maximum orientation of fibers occured at a shear rate, just before the
onset of plug flow. The presence of fiber reduced the temperature
sensitivity of the flow at a given shear rate. Die swell was reduced in the
presence of fiber. Shear viscosity of the composite was increased in the
presence of resin. Die swell was increased in the presence of epoxy resin
for composites at all shear rates. The thermal degradation of NBR and
SBR composites with and without bonding agent followed single step
degradation pattern. Thermal stability of the composites was improved
in the presence of bonding agent. The degradation of virgin elastomer
and the composites followed first order kinetics.
Description:
Department of Polymer Science and Rubber
Technology,
Cochin University of Science and Technology