**4.2. Eco-friendly material and processes**

**Company name Country Product/Service Website**

Supplier of industrial level and lab-

Lab-scale electrospinning setup and semi-industrial level electrospinning machines Contract manufacturing of

Supplier of industrial level and labscale electrospinning machines and

Supplier of lab-scale and semiindustrial level electrospinning

machines

nanofibers

accessories

Inovenso Turkey Supplier of industrial level and lab-

Yflow Spain Supplier of lab-scale and industrial

setups

Yinglan Lab China Scaling-up melt electrospinning

**Table 2.** Companies supplying mass production machines

Iran Supplier of industrial level and lab-

Custom manufacturer of electrospinning machines and accessories, both basic and industry

**4. Prospects of electrospinning technology for non-woven fabric**

Different measures have been adopted to improve the productivity of electrospinning for nonwoven fabric production [56], however, limited output still exists compared with traditional processes. Needleless electrospinning has shown great potential having advantages over needle-based lines, but a lot of problems remain to be solved. The electrospinning conditions

scale electrospinning machines *http://www.elmarco.cz/*

scale electrospinning machines *http://anstco.com/english/indexen.html*

scale electrospinning machines *http://www.inovenso.com*

level electrospinning machines *http://www.yflow.com/*

machines *http://www.p-processing.com/*

Republic Supplier of industrial level setups *http://www.spur-nanotechnologies.cz/*

*http://www.mecc.co.jp/en/ html/nanon/list.html*

*http://www.fuence.co.jp/en*

*http://en.fnm.ir/*

*http://bioinicia.com/*Fuidnatek® *http:// fluidnatek.com/*

Elmarco

42 Non-woven Fabrics

MECC Co. Ltd Japan

Fuence Japan

ANSTCO (Asian Nanostructures Technology Company)

Fnm Co. (Fanavaran Nano-Meghyas)

Bioinicia Spain

**production**

**4.1. Productivity improvement**

SPUR

Czech Republic

Iran

Czech

The use of toxic solvents in solution electrospinning has brought about 3 main problems. First, most of the solvents used in solution electrospinning are toxic [23], such as dimethyl forma‐ mide (DMF), isopropyl alcohol, acetone, hexafluoroisopropanol (HFIP), and trifluoroacetic acid (TFA)[60], which means the whole manufacturing process from mix processing of solvents to post-processing of fibers needs a closed environment to ensure worker safety or to measure up to the required standards [61]. Extra processes increase costs and more importantly, fibers with residual toxicity for applications in biomedicine can bring about significant damage to cells [62]. Second, during the mass production process, solvent evaporation may cause a change in ambient temperature and humidity, which means an extra temperature–humidity control system is needed. More specifically, the solvent ratio in most solution systems exceeds 90% in solution electrospinning, and air humidity needs to remain below 30% [63], this means there will be an increase in the cost of mass production [62]. Third, solvent evaporation will cause tiny holes on the fiber surface – ranging from a few to dozens of nanometers in size, which weakens the strength of single fibers. In addition, it is difficult to find solvents for some special polymers at ambient temperature [64].

On the contrary, solvent-free melt electrospinning has some advantages in nature. Melt electrospinning has no complicated process route like solution mixing and recycling. The surface of the resultant fiber is smooth and the fiber has high intensity. Polymer melt is completely transformed into the target product [62]. This method can process almost all thermoplastic polymers such as polypropylene (PP)[65], polyethylene (PE)[66], polyamide (PA), polylactic acid (PLA), polycaprolactone (PCL)[67], polyethylene glycol terephthalate (PET)[68], polyphenylene sulfide (PPS), and thermoplastic polyurethane (TPU)[69]. So a stable melt electrospinning route for nanofiber mass production would be an important choice in pursuing eco-friendly manufacturing methods [63]. More attention should also be given to some water soluble polymers or modified water soluble polymers that can be solution electrospun.

#### **4.3. Fundamental research of as-pun, non-woven fabrics**

Although mountains of research work has been done on the process and fiber morphology of electrospinning non-woven fabrics, little information about the as-spun, non-woven fabrics has been revealed. Specifically, we know little about its mechanical properties including tensile strength, tearing strength, and bursting strength. The combination of electrospun non-woven fabrics with traditional non-woven fabrics or textiles should also be tested since the bonding of nanofiber to thick fiber-based substrate seems difficult.
