# Electrospinning of High-Performance Nanofibres: State of the Art and Insights into the Path Forward
## 4 Discussion
### Challenges, Limitations, and Avenues of Solutions
#### 4.2.1 Standardized Characterization Methods
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Reference** & **Polymer** & \begin{tabular}{c} **Test Method and** \\ **Specimen Preparation** \\ \end{tabular} & **Equipment** & **Gauge Length** & **Stretching Rate** & **Load Cell** \\ \hline \multirow{4}{*}{[11]} & \multirow{4}{*}{p-aramid} & Single fibre mounted on & & & & \\  & a test frame of & Agilent T150-UTM & & & & \\  & 10 mm \(\times\) 5 mm using & super glue and & Micro-tensile tester & 5 mm & 0.1 mm s\({}^{-1}\) & Minimum \\  & & double-sided tape & & & & \\ \hline \multirow{4}{*}{[16]} & \multirow{4}{*}{PAI} & Rectangular specimens & \begin{tabular}{c} CMT-8102 \\ Electromechanical \\ Universal Testing \\ Machine \\ \end{tabular} & NR & 5 mm/min & NR \\  & & & & & \\ \hline \multirow{4}{*}{[17]} & \multirow{4}{*}{PAI} & \multirow{4}{*}{Not reported} & SANS Tensile Testing & NR & 5 mm/min & NR \\  & & & & & \\ \hline \multirow{4}{*}{[33]} & \multirow{4}{*}{PBI} & ASTM D882-18 & & & & \\  & & Rectangular specimen, & 10 mm \(\times\) 70 mm, & & & \\  & & thickness of 35–50 μm, & & & & \\  & foam tape attached at & & & & & \\  & edges to avoid & & & & & \\  & clamp damage & & & & & \\ \hline \multirow{4}{*}{[26]} & \multirow{4}{*}{PBI} & Rectangular specimen & \begin{tabular}{c} Instron 3433 \\ Universal Testing \\ Machine \\ \end{tabular} & NR & 50 mm/min & NR \\  & & & & & & \\ \hline \multirow{4}{*}{[27]} & \multirow{4}{*}{PBI} & ASTM D882-12 & & & & \\  & Rectangular specimens & 100 kN Universal & NR & NR & NR \\  & & & & & \\  & & thickness of 30 μm & & & & \\ \hline \multirow{4}{*}{[32]} & \multirow{4}{*}{PBI} & Rectangular specimens & \begin{tabular}{c} Instron Testing \\ Instrument 4464 \\ \end{tabular} & 100 mm & 150 mm/min & NR \\  & & & & & & \\ \hline \multirow{4}{*}{[24]} & \multirow{4}{*}{PI-co-PBO} & Rectangular specimens & \begin{tabular}{c} CMT-8102 \\ electromechanical \\ universal testing \\ machine \\ \end{tabular} & 10 mm & 1 mm/min & NR \\  & & & & & \\ \hline \multirow{4}{*}{[43]} & \multirow{4}{*}{m-aramid} & Rectangular specimens & & & & \\  & attached to a & paper frame & & & \\ \hline \multirow{4}{*}{[49]} & \multirow{4}{*}{m-aramid} & ASTM D638 & \begin{tabular}{c} Instron 5567 \\ Universal material \\ testing machine \\ \end{tabular} & 3.18 mm & 1 mm/min & NR \\  & & & & & \\ \hline \multirow{4}{*}{[7]} & \multirow{4}{*}{m-aramid} & Rectangular specimens & \begin{tabular}{c} Fangyan YG005 \\ Electronic Single Fiber \\ Strength Tester \\ \end{tabular} & NR & 10 mm/min & NR \\  & & & & & \\ \hline \multirow{4}{*}{[15]} & \multirow{4}{*}{m-aramid} & Rectangular specimens & Kawabata Evaluation & & & \\  & of 20 mm \(\times\) 50 mm & System (KES-G1) & NR & 100 mm/min & NR \\ \hline \multirow{4}{*}{[45]} & \multirow{4}{*}{m-aramid} & ASTM D638 Type V & Instron 3343 & & & \\  & & Dog-bone-shaped & Universal testing & 7.62 mm & 1 mm/min & NR \\  & & specimens & machine & & & \\ \hline \multirow{4}{*}{[48]} & \multirow{4}{*}{m-aramid} & ASTM D638 & \
\begin{tabular}{c} Instron mechanic \\ static tester \\ \end{tabular} & NR & 5 mm/min & NR \\  & & & & & \\ \hline \multirow{2}{*}{[47]} & \multirow{2}{*}{m-aramid} & Rectangular specimens & Kawabata Evaluation & & & \\  & of 20 mm x 50 mm & System (KES-G1) & NR & 100 mm/min & NR \\ \hline \multirow{4}{*}{[47]} & \multirow{4}{*}{m-aramid} &
\begin{tabular}{c} NR\(-\)not reported. \\ \end{tabular} & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Test methods for assessing the mechanical strength of nanofibres. The type of equipment used to assess the strength of nanofibrous membranes presents a second challenge for the characterization of their mechanical performance. A universal tensile testing machine is often used to assess the mechanical strength of nanofibres. However, this equipment is not well adapted to nanomaterials due to the difficulty of mounting a nanofibre onto a test frame. The precision of the load cells also causes the measurements made with universal tensile testing machines to be generally inaccurate for nanofibres with diameters below 100 nm [42].