Conductive nylon fiber

Antistatic and conductive nylon fibers with improved performance and durability can be prepared by spinning. Since most of conductive additives are inoiganic particles, conductive fibers are generally obtained by composite spinning. However, antistatic nylon fibers are laigely produced by blend spinning because lots of antistatic additives are organic materials. 

Among carbon fillers, carbon black is most commonly used due to good conduction performance, and metallic oxides are often used to make fiber white. Du Pont produced a composite nylon fiber made up of nylon sheath and conductive polymer core formed by dispersing about 30% carbon Hack in LDPE matrix. When the conductive core content was ca. 4%, the was around 10 cm[96,97]. Toray[98] developed a composite nylon fiber made up of nylon-6 sheath and conductive polymer core formed by dispersing about 30% carbon black in nylon-6 matrix. When the conductive core content was ca. 5%, the was 10 to 10 cm. Other conductive nylon fiber was reported by Unitika[99,100], in which 25% acetylene black was dispersed in nylon-6, which was combined with the same nylon 6 base polymer at a ratio of20/80. The conductive polymer was exposed onto the fiber surface to increase efficiency. A white-colored conductive nylon fiber was also obtained by using titanium dioxide particles with diameters of 2 pm or less coated with tin oxide. A heat resistant conductive nylon fiber was obtained by dispersing carbon black in an aromatic polyamide[101]. 

Bicomponent technology has been used to introduce functional and novelty effects other than stretch to nylon fibers. For instance, antistatic yams are made by spinning a conductive carbon-black polymer dispersion as a core with a sheath of nylon (188) and as a side-by-side configuration (189). At 0.1—1.0% implants, these conductive filaments give durable static resistance to nylon carpets without interfering with dye coloration. Conductive materials such as carbon black or metals as a sheath around a core of nylon interfere with color, especially light shades. 

Nanocable chemosensors have been formed in which an inner core fiber filament is further modified by polymerization of the conducting polymer on its surface. This was first described for sensing by Zhang et al. in which a carbon fiber was used as the template for the electrochemical polymerization of a thin film of PANI [27]. The resulting nanoelectrode sensor was used to detect changes in pH resulting from the level of protonation in the polymer backbone. PPy nanofibers have been formed by the electrospinning of nylon fibers. 

A conductive composite fibers based on MWCNTs and nylon-6,6 by electrospinning was also prepared by stable dispersions of MWCNTs functionalized with -NH2 terminations in formic acid. 

A simple and convenient method of polymer modification is to introduce an additive. This method is most effectively utilized in the modification of nylon fibers. For antistatic and conductive properties, hygroscopic polymeric materials and conductive materials such as carbon and metal powders are incorporated, respectively. For flame retardant properties, antimony trioxide is added. To impart ultraviolet shielding properties, ultraviolet absorbents are included and inoiganic particles of metal such as silver and zeolite containing metal ions are used for antibacterial and odor preventing properties. 

The bacteria cell density after incubation for 18 h at 37°C decreased dramatically from 2.5 x 10" to 2.0 X 10 cells/mL for PLA, while for nylon fibers, the cell density increased rapidly to 1.7 x 10 cells/mL. Similar results were obtained, even when the test was conducted after washing the PLA fibers 10 times with nonionic detergent. Furthermore, blending polyester or cotton fibers with PLA fibers did not strongly reduce the bacteriostatic property [3]. 

Hong, K. H., K. W. Oh, and T. J. Kang (2005). Preparation of conducting nylon-6 electrospun fiber webs by the in situ polymerization of polyaniline. Journal of Applied Polymer Science 96(4) 983-991. 

When nylon net is substituted for the glass paper, the conductivity increases by a factor of about three (sample 10). This can be attributed to the increased thermal conductivity of the nylon fibers, large fiber diameter, and to the lack of contact resistance between the individual fibers because the strands are fused together with a binder. 

Other workers have used similar principles to enable continuous production of conducting polymer fibers in a flow-through electrochemical cell. As with the hydrodynamic system above, polymer is produced at the anode and continuously removed from the cell in the form of a fiber. Alternatively, other fibers such as kevlar or nylon can be coated using such hydrodynam-ically controlled polymerization systems. 

Further studies were conducted on the bending performance of nylon 6 electrospun nanofibers reinforced dental resin composites and it was revealed that the addition of 5% weight fi action improved the adhesion between nylon fibers and the matrix polymer [89],... 

Antistats such as polyoxyethylenes (151,152) and A/-alkyl polycarbonamide (153) are added to nylon to reduce static charge and improve moisture transport and soil release in fabrics. These additives also alter the luster of fiber spun from bright polymer. Static reduction in carpets is achieved primarily by the use of fibers modified with conductive carbon black (see Antistatic agents Carbon, carbon black). 

Polyamides (nylons) are thermoplastic fibers that retain their form produced by heat treatment. They are usually given an alkaline scour and then heat-set. The heat-setting treatment is conducted at ca 10°C above the subsequent wet processiag steps this ensures good form retention after processiag. Woven fabrics are usually heat-set on a contact heat-setting machine and nylon tricot is generally heat-set on a tenter frame or ia steam chambers. 

While carbon fiber (thickness on the order of 1000 nm) composites offer very strong materials, carbon nanotubes make even stronger composites. These carbon nanotubes have aspect ratios of over 1000 (ratio of length to diameter). Further, because some carbon nanotubes are electrically conductive, composites containing them can be made to be conductive. A number of carbon nanotube matrixes have been made including using a number of engineering resins, such as polyesters, nylons, polycarbonates, and PPE. 

Electrodes in a capacitively coupled conductivity detector were made by injection molding carbon-filled polymer into a preformed PS chip. The polymer consisted of three conducting formulations 8% carbon black filled PS, 40% C fiber filled nylon-6,6, and 40% C fiber filled high-impact PS [774]. In another report, a movable contactless conductivity detector was also developed to allow the distance of the electrode to be adjustable [775],... 

---