Preparation and characterization of nanohydroxyapatite-based nanocomposites derived from immiscible blends of thermoplastic polyurethane and polydimethylsiloxane rubber

Abstract

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.