Facile preparation of highly exfoliated and optically transparent polycarbonate (PC)/clay mineral nanocomposites using phosphonium modified organoclay mineral

• Optically transparent polycarbonate (PC)/clay mineral nanocomposites have been prepared using phosphonium modified clay mineral.
• The phosphonium modified clay mineral showed outstanding thermal stability at the processing temperature of PC (280 °C).
• Highly exfoliated morphology of the clay mineral was evident in the PC/clay mineral nanocomposites.
• The thermal and mechanical properties were significantly improved at very low loading of clay mineral.
• The retention of optical transparency occurred without development of any colour in the nanocomposites.

Here, we focus on the morphology, mechanical and optical properties of the polycarbonate (PC) in the PC/clay mineral nanocomposites prepared through both the melt and solution blending technique at two different loadings (0.5 phr and 1 phr) of propyl triphenyl phosphonium modified montmorillonite (PTPP-Mt). The modified organo-Mt was prepared by ion exchange reaction and verified through FTIR spectroscopy, EDS study and XRD analysis. The outstanding thermal stability of the PTPP-Mt at the processing temperature of PC (280 °C) made it a suitable candidate for the preparation of optically transparent PC/Mt nanocomposites. The XRD analysis over the PC/PTPP-Mt nanocomposites revealed the destruction of ordered geometry of the clay mineral, whereas, the presence of some localised zones of Mt was evident from transmission electron microscopic (TEM) analysis. Thermal analysis indicated an increase in glass transition temperature (Tg) and thermal stability of PC in the nanocomposites. The strength and modulus of the nanocomposites were increased with increase in Mt loadings. An increase in storage modulus in the nanocomposites was evident from the thermomechanical studies. Finally, the optical transparency of PC was retained without generation of any colour in the PC/PTPP-Mt nanocomposites.

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