An organic-inorganic polymeric alumina hybrid nanocomposite

Abstract

An organic-inorganic hybrid-nanocomposite of poly(2-acrylamido-2-methyl-1-propane sulfonic acid sodium salt) and Al2O3 with nano-alumina particles was synthesized in two steps. Firstly, the surface of nano-alumina particles was modified by 3-methacryloxy-propyl-trimethoxysilane as a coupling agent by sol-gel method. Secondly, the surface modified nano-alumina particles were grafted onto the poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) by free radical polymerization. The spectral (FTIR spectroscopy) and thermal (TGA) methods, verified the participation of coupling agent, polymer and aluminum oxide (alumina) into the hybrid structure. Introduction of silanol groups into the alumina particles leads to a better distribution of particles into the polymeric matrix. The results also showed four steps of weight loss for the hybrid nanocomposite, which includes about 80% weight loss until 700°C and 20% of char yield, which is due to presence of alumina, silica and sodium oxide in hybrid nanocomposite. SEM and TEM studies confirmed that the nano-alumina particles have been spherical and homogeneously dispersed throughout the sample with dimensions in the range of nanosizes inside the nanocomposite sample containing 5 wt % of Al2O3. The analysis of thermo-mechanical properties of homopolymer and its nanocomposite revealed the shift in storage modulus and tanδ peaks that was attributed to morphological changes in the nanocomposites due to the amount of inorganic nano-particles and their distribution in polymer matrix. The adsorption behavior showed that hybrid nanocomposites have ability for interaction with heavy metal ions by means of adsorption through interaction between the oppositely charged functionalities and metal ions. However, it was found that the adsorption efficiency of the hybrid nanocomposite is much better than that of its pure polymer.