# Electrospinning of High-Performance Nanofibres: State of the Art and Insights into the Path Forward
## 4 Discussion
### Challenges, Limitations, and Avenues of Solutions
#### 4.2.2 Dissolution  
The dissolution of high-performance fibres continues to be a challenge in electrospinningning. The high mechanical properties of these polymers are often associated with a high crystallinity, making their processing difficult [35]. Furthermore, the chemical resistance of the polymers can be considered a major limitation of electrospinningning with these polymers, as some are incompatible with common organic solvents. This is especially an issue for p-aramid and PBO, which cannot be directly dissolved in a volatile solvent and must either be modified at the polymer level or spun from a precursor [3; 24]. The use of such modifications is helpful in allowing for the electrospinningning of these high-performance fibres. However, the complexity of the process may limit industrial implementation. As poly mers cannot be bought from manufacturers and directly dissolved, the process becomes increasingly complex.  
Other polymers, such as m-aramid, PAI, and PBI, are able to be directly dissolved into organic solvents such as DMAc. They may still require the use of an aprotic salt to encourage dissolution, but it is generally thought to be an effective and simple method to produce a polymer solution [11]. At the lab scale, processes involving organic solvents can be easily controlled to minimize risk. Therefore, the processing of polymers into a solution for electrospinning is a relatively facile procedure that can be easily replicated. At this stage, the majority of high-performance nanofibre electrospinningning is occurring in small-scale lab settings. However, the scale-up of electrospinning may become challenging with the use of toxic and flammable solvents, both within the workplace as well as for users who may be exposed to residual solvents within the nanofibres [55]. Industrial scale-up relies largely on needleless electrospinningning methods, where the polymer solution may be exposed to air before electrospinningning, as opposed to enclosed within a syringe. Large-scale electrospinningning equipment is also more difficult to contain within a fume cabinet, which is a common option at the laboratory scale. Therefore, the use of solvents that are highly volatile, toxic, flammable, and/or environmentally harmful is concerning for the scale-up of the production of these nanofibres. When possible, it may be advantageous to consider organic solvents with lower toxicity as solvents for high-performance fibres. In the case of PAI, for example, a variety of organic solvents may be used to dissolve the fibre for electrospinningning [54]. Generally, the choice of solvent is made based on the dissolution efficiency and solution properties. However, considering the toxicity, flammability, and environmental impacts of the solvent at an early stage of research may help with later industrial scale-up. Where a toxic solvent is necessary for good dissolution, blending this solvent with a non-toxic or environmentally friendly solvent may be an option to reduce toxicity without compromising solution properties [68].