Comparative studies on Al₂O₃ based nanocomposites of some speciality polymers and binary polymers with the corresponding SiO₂, MnO₂ and ZrO₂ based nanocomposites

Abstract

Al₂O₃, based nanocomposites of speciality polymers such as poly-N-vinylcarbazole (PNVC), polypyrrole (PPY) and polythiophene (PTP) and of binary polymers PNVC-PPY, PNVC-PTP or PNVC-PANI were prepared and characterized by FTIR spectroscopic analyses. General bulk properties such as thermogravimetric stability, morphological features (SEM) and particle sizes (TEM) were investigated and compared with those reported with other nano-oxide (SiO₂, ZrO₂, MnO₂) based polymers prepared by similar procedures. Thermal stabilities of the polymer-metal oxide composites and of the binary polymer- Al₂O₃ based composites were appreciably improved compared to the same for the unmodified base polymers. SEM analyses revealed the presence of lumpy aggregates of smaller particles forming a ‘raspberry’ morphology pattern. TEM studies showed formation of spherical particles of sizes varying between 24-500 nm depending on the nature of the oxides and monomers used. The d.c. conductivities of the composites were in the range of 10^-5-10^-7 S/cm<i> </i>for the PNVC based systems including the binary copolymer composites, 10^-2-10^-4 S/cm for PPY -based systems, 10^-3 S/cm for PTP-based systems and (0.03-6.1)×10^-2 S/cm for PANI-based systems. The nature of the metal oxide counterpart did not influence the conductivity values. These composites were dispersible in aqueous medium-the dispersion stabilities being different from system-to-system depending on the polymers and the nature of the oxide counterpart.