Liquid crystalline polymers XVI*. Thermotropic liquid crystalline copoly(arylidene-ether)/TiO2 Nanocomposites: synthesis, characterisation and applications

摘要

Polymer nanocomposites are already a part of many important worldwide businesses. Among many nanocomposite precursors, titanium dioxide (TiO2) nanopowder is increasingly being investigated due to its special properties. In this work, the feasibility of synthesising a new series of materials, copoly(arylidene-ether)/titanium dioxide nanocomposites, using in-situ copolymerisation technique has been investigated. This can be performed by the interaction of both cyclohexanone and 4-tert-butylcyclohexanone monomers with 4,4 '-diformyl-2,2 '-dimethoxy-alpha,omega-diphenoxyalkanes Ia-e, respectively, using different additions of titanium dioxide-P25. The structure of the prepared nanocomposites IIa-e/TiO2 (0.2-3.0%) was confirmed by elemental analysis (energy dispersive X-ray spectroscopy) and spectral data (Fourier transform-infrared [FT-IR]). FT-IR verified the dispersion of nanofillers in the copolymer. Then, the characterisation and applications of these nanocomposites are extensively discussed depending on the investigation of how the addition of titanium dioxide nanoparticles affected on their properties using various techniques, such as X-ray diffraction, SEM, transmission electron microscopy, Water Contact Angle (WCA), thermogravimetric analysis, differential thermogravimetric, differential thermal analysis (DTA), polarising optical microscope and UV-vis absorption spectroscopy. The nanoparticles affected on the copolymer thermal behaviour in different ways (discrepancy results) depending on how these nanoparticles are dispersed in the copolymer matrix. UV-vis absorption spectra displayed a decrease in the optical band gap of some nanocomposites, which resulted from the addition of titanium dioxide to these copolymers, and this can improve the efficiency of them as organic emitting materials.