posted on 2016-02-08, 00:00authored byTitash Mondal, Rana Ashkar, Paul Butler, Anil K. Bhowmick, Ramanan Krishnamoorti
Grafting of high molecular weight
polymers to graphitic nanoplatelets
is a critical step toward the development of high performance graphene
nanocomposites. However, designing such a grafting route has remained
a major impediment. Herein, we report a “grafting to” synthetic pathway by which high molecular weight polymer,
poly(ε-caprolactone) (PCL), is tethered, at high grafting density,
to highly anisotropic graphitic nanoplatelets. The efficacy of this
tethering route and the resultant structural arrangements within the
composite are confirmed by neutron and X-ray scattering measurements
in the melt and solution phase. In the semicrystalline state, X-ray
analysis indicates that chain tethering onto the graphitic nanoplatelets
results in conformational changes of the polymer chains, which enhance
the nucleation process and aid formation of PCL crystallites. This
is corroborated by the superior thermal properties of the composite,
manifested in accelerated crystallization kinetics and a significant
increase in the thermal degradation temperature. In principle, this
synthesis route can be extended to a variety of high molecular weight
polymers, which can open new avenues to solution-based processing
of graphitic nanomaterials and the fabrication of complex 3D patterned
graphitic nanocomposites.