Preparation of magnetic poly(vinyl alcohol) (PVA) materials by in situ synthesis of magnetite in a PVA matrix

An easy method for manufacturing homogeneous inorganic-organic materials, especially composite fibers, was obtained by the in situ synthesis of inorganic particles within polymer matrices. In this article, nanosized magnetite particles were synthesized in situ within poly(vinyl alcohol) (PVA) solutions by precipitating Fe2+ ions or a mixture of Fe2+ and Fe3+ ions with NaOH solution. As a result, magnetite particles with an average diameter of 20 nm were obtained homogeneously within the solutions because of the tridimensional structure and chelating capacities of PVA. Transparent films were obtained by a casting method, and six kinds of magnetic PVA fibers were also prepared by a wet-spinning method from the solutions containing magnetite nanoparticles. The mechanical properties and the saturation magnetization of the fibers were measured. These fibers, which contain iron ions with a maximum content of 17.63 wt %, can be successfully fabricated by the in situ synthesis and they exhibit excellent magnetization properties (i.e., the largest saturation magnetization is 13.38 emu/g). (C) 2002 Wiley Periodicals, Inc.