Preparation And Properties Of Electromagnetic Functional Composite Membrane Based On Bacterial Cellulose

Bacterial cellulose (BC) is a new type of renewable and non-polluting biological materials, with unique three-dimensional network architecture. There are many active hydroxyl on its surface, which make it highly reactive to lead and control the morphology of functional nano-composite materials during the synthesis process. Due to its flexibility, machinability and good mechanical properties, BC can be used as a high-performance composite matrix.The cobalt ferrite (CoFe2O4) is a material with excellent performance of soft magnetic. It has excellent magnetic property, such as high saturation magnetization, high coercivity, and magnetic anisotropy. It has excellent chemical stability and resistance to corrosion and abrasion. All these make it can be applied in the vertical magnetic recording, magnetic and optical devices, microwave device, and electromagnetic shielding materials. Polypyrrole (PPy) is one of the most common used conducting polymers because of its high conductivity, mild preparation conditions, low-cost preparation, non-toxicity and good stability. But the low solubility, infusibility and low mechanical property of PPy restrict its processing and applications.In this work, CoFe2O4/BC magnetic composite membranes were firstly prepared by in situ composite and coprecipitation, then focused on exploring the influencing factors on the structure and properties. After that, flexible PPy/CoFe2O4/BC functional membranes with conductivity and electromagnetivity were prepared by in situ chemical synthesis. The work details shown as follows: (1) CoFe2O4/BC membranes were prepared and discussed. The influence of monomer concentration and adding PVP as the surfactant were studied. Then the composite membranes were characterized by FE-SEM, FTIR, XRD, PPMS, EA, TGA and so on. The results showed that the best magnetic property was achieved when the cobalt ion concentration was0.07mol/L, and the saturation magnetization rate can reach14.25emu/g. The nano-cobalt ferrite agglomeration was obviously improved and the dispersion is more uniformly by adding the PVP surfactant;(2) PPy/CoFe204/BC membranes were prepared and discussed. By changing the pyrrole monomer concentration and the cobalt iron ion concentration, an orthogonal experiment was set up. The composite membranes were characterized by FE-SEM, FTIR, XRD, PPMS, EA, TGA and so on. The results revealed that composite membrane conductivity increased with the increase of pyrrole monomer concentration in the early stages. After that, the conductivity gradually becomes stable in0.4S/cm. The PPy/CoFe2O4/BC composite membranes had an electromagnetic shielding function with the SE close to30dB, which could meet the need for daily life.