| As a kind of functional film, magnetic polymer film can be used in the military and domestic areas. At present, traditional magnetic composite films couldn't have higher quality. It's also difficult to prepare magnetic polymer film using structure type polymers due. A new generation film is available which is called organic-inorganic nanostructure magnetic composite film. But present preparing methods are difficult to make nanoparticls array ordered. Moreover, they usually require severe preparing condition. The paper presents a new preparation method of such film by in-situ chemical transformation with film phase permeation. Such film is composed of magnetic particles and micro-porous polyvinyl difluoride (PVDF) film. Four factors are taken into account: concentration of ferrous chloride and sodium hydroxide, reaction temperature and time. Effects of different onditions on appearance, magnetic susceptibility, and the content of iron element are studied and the optimum preparation conditions are obtained. X-ray diffraction and Infrared spectrum demonstrate that the magnetic particles in film are nanoscale Fe3O4. Research of Infrared spectrum and DSC curve indicate that there is no chemical bond between Fe3O4 and PVDF. Fe3O4 particles exist in the form of metal oxide particles. However, there is some force between Fe3O4 and fluorine atom.In order to make clear the effects of Fe3O4 on composite film structure, the thickness, porosity, average and maximum pore size, pore size distribution of different films are measured. Surface morphology is studied by scan electronics microscope (SEM). The characterizing results of film micro-morphology showed that pore structure of Fe3O4/PVDF composite film were better than those of PVDF host film. Compared with host film, thickness and porosity of composite film change not much, while average and maximum pore size decrease, and pore size distribution range become narrow. Further more, controlling reaction time can control the content of in-situ transforming Fe3O4.The permeation rate of N2, O2, CO2, the thermal infrared emissivity and radar absorption of composite film were measured. It showed the effluence of composite film on the permeation rate of O2 is more obvious than that of N2 and CO2. But there is no apparent effect on their separation. Compare with host film, thermal-infrared radiance of composite film decreased. To certain extent, composite film has radar absorption ability. |
PDF Full Text Request