2.5.6. Determination of Self-Healing Performance

The samples were cut into dumbbell-shaped samples, and five points were randomly selected on the dumbbell-shaped samples to measure the thickness using a desktop thickness gauge, and the average value was taken. The USA Instron 3369 universal tensile testing machine was used to test the tensile strength and elongation at break at 100 mm/min, and the average value of each sample was measured after 5 times.

The dumbbell-shaped standard sample was cut from the middle position to part of the adhesion, and then the incision part was docked together. The samples were repaired under different conditions. The tensile properties of original and repaired samples were tested, and the self-healing efficiency was calculated by using the following Equation (2):

$$
\mathfrak{m}\% = \mathfrak{a} / \mathfrak{a}\_0 \times \mathbf{100\%}\tag{2}
$$

where η is self-healing efficiency, σ is fracture strength of repaired specimen and σ<sup>0</sup> is fracture strength of the original sample.
