## 3 Results and Discussion
### The Effects of Different Monomer Ratios on the Performance of the Various Synthesized PSA Emulsions
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Serial** & **Monomer Ratio** & **PDI** & **D\({}_{\text{g}}^{\text{DLS}}\)** & **Zeta Potential** & **Solid** & **Conversion** & **T\({}_{\text{g}}\)** & **MFFT** \\
**Number** & **(St:BA)** & **PDI** & **(nm)** & **(mV)** & **(\%)** & **Rate (\%)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** \\ \hline SA1 & 1:9 & 0.063 & 160.9 & \(-61.0\) & 48.8 & 95 & \(-42.4\) & \(<\)\(-5\) \\ SA2 & 2:8 & 0.050 & 153.8 & \(-52.5\) & 50.0 & 98 & \(-26.6\) & \(<\)\(-5\) \\ SA3 & 3:7 & 0.032 & 160.3 & \(-50.1\) & 49.8 & 98 & \(-11.9\) & \(<\)\(-5\) \\ SA4 & 4:6 & 0.047 & 159.4 & \(-54.3\) & 49.3 & 96 & 1.5 & \(-0.4\) \\ SA5 & 5:5 & 0.063 & 151.4 & \(-51.2\) & 48.9 & 95 & 18.91 & 12.6 \\ \hline \end{tabular}
\end{table} 
Table 4: Basic properties of PSA emulsions. Figure 3: (**a**) TEM images of various PSA emulsions. (**b**) FT-IR test results of the various PSA emulsions. (**c**) Damping properties of PSA latex film. (**d**) The fracture surface of an adhesion test specimen. The chemical structures of the synthesized PSA emulsions were tested using FT-IR; the test results are shown in Figure 3b. All the prepared PSA emulsion latex films exhibit C=O stretching vibration peaks in the ester group at 1710 cm\({}^{-1}\)-1740 cm\({}^{-1}\), and C-O stretching vibration peaks in the 1050 cm\({}^{-1}\)-1300 cm\({}^{-1}\) region, which confirms the presence of ester groups in the polymer. The characteristic absorption peaks of monosubstituted benzene rings distributed at 690 cm\({}^{-1}\)-700 cm\({}^{-1}\) and 740 cm\({}^{-1}\)-750 cm\({}^{-1}\) are also found in the PSA series latex films, which effectively indicates the presence of a benzene ring structure in the polymer latexes. In addition, the characteristic peaks at 740 cm\({}^{-1}\)-750 cm\({}^{-1}\) are elevated from SA1 to SA5. This is also consistent with the presence of ester groups in the polymer. The above results prove that the molecular structures of the PSA emulsion films are the same as those of the designed structure. The damping performance results of the PSA latex films are presented in Figure 3c. As the St content increases, the damping temperature range of the latex film gradually increases and the peak value of the loss factor also gradually increases. This phenomenon is chiefly attributed to the fact that, compared with BA, St features a larger rigid steric hindrance group. On one hand, this leads to a weaker mobility of the polymer chain segments and the temperature range within which damping occurs is expanded; on the other hand, energy dissipation becomes more pronounced during the movement of these chain segments, causing the peak value of the loss factor to increase continuously. Moreover, given that the service and performance-related tests on mortar are conducted at ambient temperature, the damping performance of the PSA latex films at this temperature is ranked as follows: SA4 > SA5 > SA3 > SA2 > SA1. The adhesive property of PSA emulsions with concrete were tested using the positive tensile adhesion test. The results are shown in Figure 3d and Table 5. It can be seen that as the content of St increases, the adhesion strength shows a generally increasing trend. This is because at room temperature, the latex film with a lower St content has a relatively low strength, making it prone to cohesive failure within the latex film layer. As the St content increases, the strength of the latex film gradually improves. The microscopic interlocking effect that contributes to adhesion also increases accordingly, and the adhesion strength gradually rises. This can also be inferred from the adhesion failure modes of the latex films. For SA1, SA2, and SA3, the failure mode is the rupture of the latex film itself. For SA4, adhesion failure occurs at the interface between the latex film and the concrete. For SA5, adhesion failure is a combination of the failure at the adhesion interface and the failure of the concrete matrix. The adhesion strength is significantly improved at room temperature.