# Design and Performance of a Novel Scalable Core–Sheath Inverted Nozzle Soft Material Pressure Spinner

## TL;DR

A new scalable method for making core-sheathed polymer fibers is developed using a unique nozzle design and gas-assisted spinning.

## Contribution

The CsINPG process enables large-scale production of core-sheathed micropolymeric fibers with diameters under 10 μm.

## Key findings

- The CsINPG system uses centrifugal force and pressure to produce uniform core-sheathed fibers.
- Optimized parameters yield fibers with average diameters <10 μm.
- The process supports 'green polymers' like alginate and cellulose via water bath conversion.

## Abstract

Core–sheathed inverted nozzle
pressurized gyration (CsINPG)
is a novel fiber manufacturing process based on gas blowing-assisted
rotary coaxial spinning technology, capable of large-scale manufacture
of core–sheathed, micropolymeric structures. The CsINPG spinning
vessel is constructed from polycarbonate and has a unique nozzle arrangement,
which increases uniformity and facilitates the formation of core–sheathed
fibers. The CsINPG apparatus functions as a jet generator, ejecting
the spinning feedstock under the combined forces of centrifugal force
and pressure differentials. The centrifugal force, which is generated
by the spinning of the vessel, is powered by a connected electrical
motor. This enables the loaded polymeric feedstock to overcome its
surface tension, facilitating fluid ejection through the external
nozzles on the vessel wall to form spinning jets. These polymeric
jets undergo further stretching through the assimilation of the pressure
differential, which is powered by introducing nitrogen flows. This
further increases the initial velocity and acceleration. In core–sheathed
pressurized gyration, the feedstock is present in two different chambers
of the core and the sheath. Furthermore, during “inverted”
nozzle-pressurized gyration, the entire manufacturing process is carried
out on a horizontal axis, facilitating the controlled streaming of
these spinning jets into a water bath. This facilitates the usage
of “green polymers” such as alginate and cellulose,
which require water baths to be converted from soluble streams to
insoluble fibrous structures. These fabricated core–sheathed
fibers, manufactured under the optimum parameters in this study, produced
fibers with average diameters measuring <10 μm. This paper
will delve into the development of the novel CsINPG manufacturing
process, focusing on the design of the spinning vessel, the parameters
used, the optimization of parameters and their consequences, and the
potential future applications of the manufactured core–sheathed
fibers.