Fabrication of Iron Nanoparticle Reinforced Polyacrylonitrile Nanocomposites

1. 280 oC 280 oC 280 oC 280 oC 270 oC 290 oC 225 oC 280 oC 275 oC 280 oC In air 275 oC In hydrogen In air In argon In argon In hydrogen In argon In hydrogen 280 oC 900 oC In air In argon In air In hydrogen 300 oC 460 oC 550 oC 420 oC In argon 345 oC 570 oC 470 oC 600 oC 570 oC 450 oC 780 oC 620 oC 450 oC 580 oC 610 oC 830 oC 620 oC 450 oC 900 oC 900 oC 900 oC 620 oC in Argon 450 oC 450 oC 450 oC 805 oC >1000 oC 720 oC 905 oC 850 oC 630 oC 680 oC 680 oC >1000 oC 700 oC >900 oC >900 oC 320 oC Fabrication of Iron Nanoparticle Reinforced Polyacrylonitrile Nanocomposites In air 350 oC 650 oC Ruby Chung, Zhanhu Guo (Ph.D.) and H. Thomas Hahn (Ph.D.) Multifunctional Composites Lab, Mechanical and Aerospace Engineering Department University of California Los Angeles, Los Angeles, CA 90095, USA INTRODUCTION Thermal Properties of Fe Nanocomposites SEM Images of Polyacrylonitrile Polymeric composites reinforced with inorganic fillers have attracted much interest due to their reduced weight, high homogeneity, cost-effective processability and tunable physical such as mechanical, magnetic, optical, electric and electronic properties. The applications have extended into the marine (Naval submarine) and airplane (Boeing 787) industries. Furthermore, Results: TGA Results: DSC • Around 125°C is the glass transition temperature, Tg, of 80 wt% Fe • The composite releases heat at lower temperature due to the oxidation of Fe NPs Pure PAN is stable until 300 degrees C then it decomposes until no PAN is left. On Fe PAN, the first dip is due to evaporation of DMF. The rise in weight percentage is due to oxidation then Fe PAN decomposes until they become stable above 500 degrees C. The circled part indicates where iron oxide reduces to Fe. The final product is stabilized Fe species. , nanoparticles (NPs) within the polymeric matrix render the nanocomposite potential electronic device applications such as fuel cells, photovoltaic (solar) cells, batteries and magnetic data storage. On the other side, the functional groups of the polymer surrounding the nanoparticles enable these polymer nanocomposites suitable for variable applications such as site-specific molecule targeting application in the biomedical areas. Figure (a) microstructure of PAN Figure (b) microstructure or PAN in DMF Particle dispersion together with the interaction between fillers and polymer matrix are major challenges in the polymer composite manufacturing. The particle agglomerates and voids resulting from the poor bondage will serve as defect generating a deleterious physical properties such as lower tensile strength for structural material application and poorer electron transport path for integrated polymer composite electric/electronic device applications. We have demonstrated strengthened polymer nanocomposite fabrication by surface engineering the particles. However, functionalization is an extra cost for production with high particle loading. We developed several simple and low-cost methods (surface-initiated-polymerization, monomer stabilization method, and solvent-extraction approach). Polymer nanocomposites were developed into a granular giant magnetoresistance (GMR) sensor with the highest signal among these systems. Compared with metallic matrix GMR, the polymer matrix could be facile fabrication, low-cost usage without any packaging requirement and suitable for harsh environmental applications, ready to be used in specific biomedical areas. As seen in the SEM, DMF has successfully dissolved PAN and destroyed the microstructure. Annealing Environment Fe/PAN (40wt%, TGA) Fe/PAN (10wt%, TGA) Fe/PAN (20wt%, TGA) Fe/PAN (30wt%, TGA) EXPERIMENTALS Pure PAN (TGA) • Materials • Polyacrylonitrile (PAN) • Dimethylformamide (DMF) PAN is an organic polymer of acrylonitrile used in manufacture of useful plastics. DMF is a clear, organic, polar aprotic solvent. • Transmission electron • microscopy of Fe particles • Composite Fabrication 10 wt% 20 wt% 30 wt% 40 wt% Kinetic Study • Characterizations • Scanning Electron Microscope (SEM) • Thermogravimetric Analysis (TGA) • Differential Scanning Calorimetry (DSC) References Concluding Remarks Prospectus • Acknowledgement • MCL lab group members • Professor D. P. Young, Physics Department, Louisiana State University • A novel approach to nanocomposite fabrication was discovered. • The best concentration of PAN in DMF solution was determined to be 0.087g/ml. • The highest Fe nanoparticle loading was determined to be 80 wt%. • The pure polyacrylonitrile was stable to 300 degrees Celsius, whereas the composites decomposed until they became stable above 500 degrees Celsius. • Around 125°C is the glass transition temperature, Tg, of 80 wt% Fe. • The composite releases heat at lower temperature due to the oxidation of Fe NPs. • The addition of the Fe NPs favors the decomposition of PAN. • "Surface Functionalized Alumina Nanoparticle Filled Polymeric Nanocomposite with Enhanced Mechanical Properties" Z. Guo, et al. Journal of Materials Chemistry, 16, 2800-2808 (2006) • "CuO Nanoparticle Reinforced Vinyl-ester Resin Nanocomposites: Fabrication, Characterization and Property Analysis" Z. Guo, et al. Composites Science and Technology, 67, 2036-2044 (2007). • Flexible High-loading Particle Reinforced Polyurethane Magnetic Nanocomposite Fabrication through Particle Surface Initiated Polymerization" Z. Guo, et al. Nanotechnology, 18, 335704 (2007). • "Magnetic and Electromagnetic Evaluation of the Magnetic Nanoparticle Filled Polyurethane Nanocomposites" Z. Guo, et al. Journal of Applied Physics, 10, 09M511 (2007). • Strengthening and Thermal Stabilization of Polyurethane Nanocomposites with Silicon Carbide Nanoparticles by a Surface-Initiated-Polymerization Approach Z. Guo, et al. Composites Science and Technology, 68, 164-170 (2008). • Determine the change in conductivity due to annealing • Determine magnetic properties • Analyze final product by X-ray Diffraction Spectroscopy or Selected Area Electron Diffraction