*3.5. Analysis of the Experimental Results of the Mechanical Property Test*

Table 5 shows the test results of the mechanical properties of samples 1–8. From this, we can easily find that with the increase in the silicone rubber content, the mechanical properties of TPSiV are significantly reduced. It is more obvious when it increases to 70%. This is because the mechanical properties of silicone rubber itself are poor and far inferior to SEBS and SBS. With the obvious increase in the content of silicone rubber, the material itself gradually showed properties closer to that of silicone rubber. In addition, according to Figure 6D,H, the partial disappearance of the "sea-island" structure in TPSiV is also one of the reasons for the obvious deterioration of the mechanical properties of the sample with a silicone rubber content of 70 phr.

**Table 5.** Mechanical properties of samples 1–8.


For a material, tensile strength, elongation at break and tensile set are the three most critical mechanical properties. Using the data shown in Table 5, we can analyze the performance change after adding the silane coupling agent KH-907. We can calculate the ratio of improvement in tensile strength and elongation at break by:

$$T = \frac{\mathcal{W}\_2 - \mathcal{W}\_1}{\mathcal{W}\_1} \tag{3}$$

where *T* is the improvement ratio of tensile strength and elongation at break, *W*<sup>1</sup> is the tensile strength and elongation at break before adding silane coupling agent KH-907, and *W*<sup>2</sup> is the tensile strength and elongation at break after adding silane coupling agent KH-907.

Since the smaller the value of the tensile set, the better the performance of the material, we use the following formula to calculate the improvement ratio of the tensile set:

$$R = \frac{M\_1 - M\_2}{M\_1} \tag{4}$$

where *R* is the improvement ratio of the tensile set, *M*<sup>1</sup> is the tensile set before adding silane coupling agent KH-907, and *M*<sup>2</sup> is the tensile strength and elongation at break after adding silane coupling agent KH-907.

By substituting the data of Table 5 into Equations (3) and (4), we obtain Table 6. According to Table 6, we found that the addition of silane coupling agent KH-907 significantly improved the mechanical strength of TPSiV; the tensile strength is increased by about 40%, the elongation at break is increased by about 30%, and the tensile set is increased by about

15%. Since we have quantitatively characterized the thickness of the compatibility layer above, we believe that the reason for the improvement of mechanical properties comes from the increase in the thickness of the compatibility layer. When the material is stretched, the interaction between the MVSR phase and SEBS/SBS phase will be closer. This closer interaction gives the material better mechanical properties and resilience.

**Table 6.** The improvement rate of mechanical properties of TPSiV after the addition of silane coupling agent KH-907.

