Abstract:
Nonblack particulate fillers most used with
thermoplastic and rubber are calcium carbonate, silica, talc and
alumina hydrates. The main characteristics, which control the
effectiveness and the dispersion of filler in the polymer, are
structure, surface area and chemical activity of filler. The
mechanical behavior of rubber-thermoplastic blends depends
greatly on interactions and compatibility that develop between
the two polymers and the filler. The main objective of this study
is to improve physico-mechanical properties of calcium
carbonate (CaCO3) filled natural rubber (NR) and low density
polyethylene (LDPE) blends using a titanate coupling agent. Two
series of NR/LDPE blends, with and without titanate coupling
agent, were prepared by varying LDPE loading from 10% to
90% at 10% intervals. 20 parts by weight of CaCO3 per 100 parts
of combined polymer was incorporated into every blend
composition. The blends were prepared using a Brabender
plasticorder by melt mixing at a temperature of 130 oC, and at a
rotor speed of 60 rpm. Physico-mechanical properties such as
tensile properties, hardness, tear strength and morphology of the
blends were studied. These properties were determined according
to ISO standards. Morphology of the tensile fracture surface of
blends was observed using a transmitted light microscopy.
Tensile strength, tear strength and hardness of NR/LDPE blends
increase with increase in LDPE loading while elongation at break
decreases. NR/LDPE blends with titanate coupling agent
exhibited enhanced properties at every LDPE loading. NR/LDPE
blends having 30% of LDPE loading showed highest tensile
strength. In this blend, NR was dispersed in LDPE matrix with
good adhesion between NR and LDPE.
