Analysis of chitosan/magnetite based films obtained by different synthesis methods.

G.A. KLOSTER; D. MURACA; MARCOVICH, NORMA E.; M. A. MOSIEWICKI

Rio de Janeiro

Conferencia; Fifth International Conference on Natural Polymers, Bio-Polymers, Bio-Materials, their Composites, Nanocomposites, Blends, IPNs, Polyelectrolytes and Gels: Macro to Nano Scales (ICNP 2017 Rio),; 2017

Water pollution is a serious problem nowadays and thus, the search for materials with new properties that allow the remediation of water containing heavy metal ions and dyes is an important issue. Some published research works report the use of polymers as adsorbents, showing an increasing interest in the development of those derived from the biomass due to environmental benefits. Chitosan is one of the most used biopolymers because of its biodegradability, hydrophilicity, non-toxicity and biocompatibility. This carbohydrate is produced from the deacetylation of chitin, a major component of crustacean shells and it is a cationic biopolymer whose amino and hydroxyl groups act as active sites for the adsorption of ionic contaminants [1]. This makes chitosan a very attractive material for water remediation. Furthermore, if a magnetic phase such as magnetite is added, the material can get new properties such as the recovery of the adsorbent after its use by using a magnet and the activation of the adsorption/desorption mechanisms via magnetic hyperthermia. The way of synthesis of these nanocomposites is very important because the size and distribution of the dispersed particles determine the properties of the material. In this work, two synthesis methods were used, being the nanocomposite films obtained by casting in both cases. The first approach is a simple one-step in situ nanoparticle chemical co-precipitation method, using iron salts and chitosan solutions as precursors. In the second one, particles are previously synthesized by the co-precipitation method [2], dried and then redispersed into the polymeric solution by ultrasonication. The films were characterized physical (SEM, TEM, contact angle, moisture sorption, total soluble mass), chemical (FTIR, X-Ray), thermal (TGA), mechanical (tensile tests) and magnetically (SQUID magnetometry). The film properties were related with the amount, the size and the agglomeration/dispersion of the magnetite nanoparticles in the polymeric matrix. While for the films where the magnetite was synthesized in situ the increase in the amount of particles generated important changes in the microstructure that affected all the other properties, in the films where the dispersion of the magnetite was obtained by ultrasonication the presence of agglomerates of iron oxide particles was observed and the dependence of the nanocomposite films properties with nanoparticle concentration were much less noticeable.