Continuous yarn from electrospun sliver

Process flow chart of obtaining continuous nanofiber yarn [Uddin et al 2009. Research Letters in Materials Science, vol. 2009, Article ID 868917, 5 pages, 2009. This work is licensed under a Creative Commons Attribution 3.0 Unported License].

Continuous yarns have been fabricated from spinning of fiber sliver for centuries. Similarly, electrospinning can be used to form nanofibrous sliver which can be used for spinning into yarns. From a piece of electrospun nonwoven nanofibrous membrane fabricated using conventional plate collector setup or aligned fibrous membrane from drum collector, narrow strips may be cut to give slivers [Zhou et al 2012]. For direct fabrication of sliver, a drum collector with narrow width [Bosworth et al 2014; Liu et al 2010] or a sharp edge disk collector [Zhou et al 2009] may be used in the collection of electrospun fibers. Fibers that are aligned on the edge of the disk may be peeled off as a sliver. Zhou et al (2009) was about to fabricate aligned polyacrylonitrile nanofiber bundles which can be carbonized to form carbon nanofiber bundles with tensile strengths and Young's moduli of 300 - 600 MPa and 40 - 60 GPa respectively. Uddin et al (2009) demonstrated the process of spinning continuous yarn from electrospun carbon nanotube-reinforced nanocomposite yarns. Sliver was made from electrospun nanofibers deposited on aluminium strip coiled around a drum. The sliver was peeled off from the aluminium strip and twisted to form continuous yarn.

The primary disadvantage of this process is that it requires electrospun slivers to be formed before combining into a continuous yarn. Construction of the sliver is also relatively slow as sufficient fibers need to be build up before it is strong enough to be handled. With the development of various techniques for in situ spinning of continuous yarns using electrospinning this method may seem to be impractical and inefficient. However, this method of spinning yarn does have some advantages over conventional electrospinning. Since sliver production and yarn spinning is not continuous, the process is able to take in any disruption in the electrospinning process. Consistency in the yarn diameter can also be better maintained by controlling the numbers of sliver. Slivers made of different materials may be combined to form a single yarn with multiple properties.