Magnetohyperthermia in a vegetable oil based polymer

D. MURACA; M. I. ARANGUREN; D. G. ACTIS; M. KNOBEL; C. MEIORIN; P. MENDOZA ZELÍS; M. A. MOSIEWICKI

Cancún

Simposio; XV Simposio latinoamericano de polímeros; 2016

Introduction The development of polymeric nanocomposites obtained from renewable raw materials has become an important area of research due to their potential applications in different scientific and industrial fields and the environmental advantages when compared to synthetic polymers. Tung oil is extracted from the seeds of the tung tree and it is a highly unsaturated oil that can be polymerized with styrene in the presence of a cationic initiator 1. Previous works have reported that some of the compositions display shape memory properties (SMP) 1. The load of these systems with nano-magnetite (NM) can increase their applications. The magnetite nanoparticles can absorb electromagnetic energy from an external high-frequency field and release it as heat, which under specific conditions, can be used to trigger the SMP of the nanocomposites 2. The aim of this work is to study the influence of NM concentration on a polymeric matrix based on tung oil and styrene. Experimental Part Magnetite nanoparticles were produced by means of co-precipitation method from an aqueous Fe3+/Fe2+ solution using excess of a concentrated solution of NH4OH and coated with oleic acid. The resulting MN have a mean size of 9.8 nm 3. Nanocomposites preparation. Styrene was added and mixed with tung oil (weight ratio of 50/50) and this step was followed by the addition of the initiator (boron trifluoride diethyl etherate). Then, a selected percent of oleic acid-coated magnetite was added and this mixture was put into an ultrasonic device to obtain a good dispersion of MN and finally, poured into the mold 3. The reactants were heated at 60°C for 12h and then at 100°C for 12h. Nanocomposites characterization: Thermogravimetric analysis were performed using a TGA-DTGA Q500 TA instrument at 10°C/min under air atmosphere. The static magnetic properties were studied using a SQUID magnetometer (Quantum Design, MPMS XL). Both isothermal magnetization curves as well as zero field cooling and field cooling (ZFC/FC) measurements were performed. Specific absorption rate (SAR) data from magnetic hyperthermia experiments were obtained from magnetocalorimetric tests using a resonant R−L−C circuit Huttinger radiofrequency (rf) field generator. The SAR values are calculated as SAR = dT/dt c/NM where T is temperature, t is time, c is the specific heat capacity of the sample and NM is the nanoparticle concentration.   Results and Discussions The isothermal magnetization and FC/ZFC tests showed that all the nanocomposites present superparamagnetic behavior at room temperature. The maximum blocking temperature (TBmax) increases as the content of NM increases in the material with values of 100, 126, 122,160 and180 K for samples with 1.5, 3, 5, 7 and 10 wt.% of NM, respectively. This behavior can be attributed to possible interactions among the particles. Figure 1 shows SAR values as a function of NM content. As was expected, the specific absorption rate increases with the content of NM in the samples. Figure 1. SAR as a function of NM content   Conclusions Hyperthermia can be possible in the nanocomposites based on tung oil for contents above 1 wt.% of magnetite. Acknowledgments: The authors gratefully acknowledge to CONICET, ANPCyT, UNMdP (Argentina) and FAPESP, CNPq (Brazil).   References 1. Meiorin, C.; Aranguren, M. I.; Mosiewicki, M. A. Polym. Int. 2012, 61, 735. 2. McBain, S.C.; Yiu, H.H.P.; Dobson, J. Int J. Nanomedicine 2008, 3, 169. 3. Meiorin, C.; Muraca, D.; Pirota, K.R.; Aranguren, M.I.; Mosiewicki, M.A. European Polymer Journal 2014,  53 (1), 90.