FERROELECTRIC FIBERS AND APPLICATIONS THEREFOR

• Main Authors: TURKEVICH, LEONID ANTHONY, MYERS, DAVID LEWIS
• Format: Patent
• Language: English; French
• Published: 27.11.1997
• Edition: 6
• Subjects: APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBONFILAMENTS; BRAIDING; CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS,THREADS, FIBRES, BRISTLES OR RIBBONS; CHEMISTRY; COMPOSITIONS BASED THEREON; COTTON-WOOL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS,NON-WOVEN FABRICS; KNITTING; LACE-MAKING; MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARYMATERIAL; METALLURGY; NATURAL OR ARTIFICIAL THREADS OR FIBRES; NON-WOVEN FABRICS; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; SPINNING; TEXTILES; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; TRIMMINGS; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; WADDING

A fiber which includes a thermoplastic polymer and particles of a ferroelectric material dispersed therein. The thermoplastic polymer may be, for example, a polyolefin, such as polypropylene or polyethylene, and the ferroelectric material may be barium titanate. The ferroelectric material may be present at a level of from about 0.01 to about 50 percent by weight (from about 0.001 to about 13 percent by volume), and will have a longest dimension in a range of from about 10 nanometers to about 10 micrometers. The fiber may be exposed to an electric field. A plurality of the fibers may be employed to form a knitted or woven fabric or a nonwoven web. Also provided is a method of preparing fibers containing particles of a ferroelectric material. The method includes destructuring the ferroelectric material in the presence of a liquid and a surfactant to give destructured particles; the liquid is a solvent for the surfactant and the surfactant is adapted to stabilize the destructured particles against agglomeration. A blend of the stabilized, destructured ferroelectric material particles and a thermoplastic polymer is then formed and extruded to form fibers. The extruded fibers may be collected on a moving foraminous support to form a nonwoven web and, if desired, may be exposed to an electric field. The fiber of the present invention, especially when in the form of a nonwoven web, is especially suited as a filtration medium. For example, the nonwoven web may be adapted to remove particulate matter from a gaseous stream.