This article holds significance in preparing nanocomposites with reasonably good strength and flexibility. Nanohydroxyapatite (nHA) and polypropylene glycol-coated nHA (PPG-nHA) were synthesized by sol–gel technique. Nanocomposites derived from immiscible blends of thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) rubber with nHA as the nanofiller were prepared by melt mixing technique and characterized. Transmission electron microscopic images display a significant extent of dispersion of modified and unmodified nHA in the blend matrices. Scanning electron microscopy results show that the incorporation of PPG-nHA leads to a reduction in the particle size of PDMS in the blends. Dynamic storage modulus against strain sweep study reveals the interaction between the polymer matrix and the filler increased by the surface coating of nHA with PPG. Surface coating of nHA with PPG led to the enhancement of physicomechanical properties of the blend nanocomposites. Thermogravimetric analysis shows the incorporation of PPG-nHA increases the degradation temperature of TPU-PDMS blends. Melt rheological studies of the blends and the blend nanocomposites reveal the shear-thinning behavior of the nanocomposites at all different filler loadings, and this shear thinning effect is more prominent in the case of composites at higher loading of the nanofiller.

Semiconducting BiVO 4 , is successfully prepared by solid-state route and attempts are taken to dope vanadium sites by titanium ions to produce BiV 1-x Ti x O 4 (x = 5%, 10% and 15%). The products are analyzed using powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. The average particle sizes are in the range of 71-82 nm. Using diffuse reflectance spectroscopy, the band gaps are estimated and fall in visible range (2.11-2.41 eV). These nanomaterials are investigated for the photodegradation of malachite green dye solution that can find application in wastewater treatment and their efficiencies are investigated by timedependent UV-Visible spectroscopy. 15% titanium doped BiVO 4 (BVO-15) showed the highest efficiency by completely degrading malachite green in 180 min under visible light irradiation. In such heterogenous processes, separation of the used nanocatalysts remain a challenge. To address this, reusable polymer nanocomposite films are prepared using thermoplastic polyurethane (TPU) to immobilize BVO-15. The polymer nanocomposite film with 0.10 g of catalyst in 1 g of TPU showed maximum efficiency (~ 96%). The powder and film catalysts are investigated for three cycles and found to be effective. Thus, they show remarkable photocatalytic activity, stability and reusability that make them suitable for the wastewater treatment.

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