Synthesis and properties of flame-retardant poly(vinyl alcohol)/pseudo-boehmite nanocomposites with high transparency and enhanced refractive index

Flame-retardant nanocomposites with high transparency based on poly (vinyl alcohol) (PVA) and pseudo-boehmite nanorods have been fabricated by synthesis of pseudo-boehmite nanorods and subsequent solution blending with PVA. The morphology and physical properties of PVA/pseudo-boehmite nanocomposites have been characterized systematically. Scanning electron microscopy investigations showed the homogeneous dispersion of pseudo-boehmite nanorods within PVA matrix even at very high nanorods loadings. The nanocomposites with 37.5 wt% pseudo-boehmite nanorods exhibit limit oxygen index (LOI) as high as 30.0 with the transmittance of more than 90% at the visible region and the enhanced refractive index. Moreover, the incorporation of the pseudo-boehmite nanorods increases the modulus and the tensile strength of PVA, indicating the significantly enhanced surface hardness of the nanocomposite. It is considered that the prepared PVA nanocomposites are not only useful as flame-retardant fibers, a long term pursued target for PVA fabrics, but also as optical appliances with its excellent transparency and high refractive index.