Composites of sPS filled with different contents of graphene nanosheets (GNS) are prepared by coagulation method. Two types of GNS with different thicknesses (denoted as G1 and G10) are studied to unveil the effect of aspect ratio on the crystallization kinetics of the composite. Atomic force microscopy and transmission electron microscopy (TEM) show that G1 is a wrinkled sheet with an average thickness of ~2 nm and that G10 is a smooth flake with a thickness of ~50 nm; both possess a basal dimension of ~5 μm. TEM studies on the melt-quenched composites reveal that G1 has a more uniform dispersion in the sPS matrix than G10. Short lamellae of sPS are observed in the G10-filled composites with GNS content higher than 0.5 wt.%. The results of wide-angle X-ray diffraction show that the produced sPS crystallites are in β form under severe cooling conditions in liquid N2. Regardless of the GNS content and type, the glass transition and equilibrium melting temperature of the sPS matrix are unchanged at ~96 and ~290 °C, respectively. Both G1 and G10 nanofillers are good nucleating agents for the heterogeneous nucleation of sPS. With increasing GNS loading, the isothermal crystallization rate of sPS increases. G10 is more effective than G1 in inducing sPS crystallization despite the higher concentration required to form the GNS network. Compared with 1D CNT nanofiller, 2D GNS is less effective in enhancing sPS crystallization through surface-induced nucleation because of the geometrical difference between the two materials.
All Science Journal Classification (ASJC) codes
- Polymers and Plastics
- Organic Chemistry
- Materials Chemistry