# Study of Mechanical Properties of Micron Polystyrene-Tughened Epoxy Resin
## 3 Results and Discussions  
### Tensile Properties of Epoxy Resins with Different PS Weight Fraction  
Table 2 shows the tensile test data of specimens doped with different weight fractions of PS microspheres, and the corresponding tensile strength, elastic modulus and elongation at break variation curves are plotted according to Table 2.  
The tensile strengths of the specimens with different PS weight fractions are shown in Figure 6. It can be seen from the figure that with the increase in the PS weight fraction, the tensile strength of the specimens shows a trend of increasing and then decreasing, and the tensile strength of the specimens increased from 62 MPa to 110 MPa with the increase in PS weight fraction from 0 wt% to 2.5 wt%, an increase of 77%. However, the tensile strength of the specimens decreases substantially when the PS weight fraction is increased further, and when the PS weight fraction is greater than 3.75 wt%, the tensile strength of the specimens is lower than that of the specimens without the addition of PS, at which time the addition of PS causes a significant decrease in the tensile strength. \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Symbol**} & **PS Weight** & **Tensile** & **Modulus of** & **Elongation at** \\  & **Fraction (wt\%)** & **Strength (MPa)** & **Elasticity (MPa)** & **Break (\%)** \\ \hline
1 & 0 & 62 & 12,088 & 0.6037 \\
2 & 1.25 & 99 & 29,641 & 0.3378 \\
3 & 2.50 & 110 & 29,945 & 0.4097 \\
4 & 3.75 & 55 & 12,763 & 0.5494 \\
5 & 5 & 43 & 11,069 & 0.39415 \\ \hline \end{tabular}
\end{table} 
Table 2: Tensile test data of epoxy resin colloid with different PS weight fractions. Figure 5: Impact performance test. The elastic moduli of the specimens with different PS weight fractions are shown in Figure 7. The trend of the elastic modulus of the specimens with different PS weight fractions is similar to that of the tensile strength, both showing an increase and then a decrease. However, the difference is that when increasing the PS weight fraction from 0 wt% to 1.25 wt%, the elastic modulus of the specimens increases substantially from 12,087 MPa to 29,641 MPa, an increase of 145%, which is significant; continuing to increase to 2.5 wt%, the elastic modulus increases less (only 2.7%), which is not much different from the PS weight fraction of 1.25 wt%. Continuing to increase the PS weight fraction, the modulus of elasticity of the specimens decreases sharply to a level close to that of the specimens without PS addition, so that the modulus of elasticity peaks at weight fractions of 1.25 wt% and 2.5 wt%. The elongation at break of the specimens doped with different weight fractions of PS is shown in Figure 8. It can be seen that the trend of elongation at break is different from that of tensile strength and modulus of elasticity. The elongation at break of the specimen was maximum when the weight fraction of PS was 0 wt%. As the weight fraction of PS increased, the elongation at break of the specimens decreased, and the elongation at break decreased from 0.6037 to 0.3378 with the addition of a small amount of PS, a decrease of 44%, and it can be concluded that a certain amount of PS doping will significantly reduce the elongation at break of the specimens [30]. However, a further increase in PS doping increases the elongation at the break of the specimens, and at a PS weight fraction of  
Figure 6: Tensile strength of specimens with different PS content. Figure 7: Elastic modulus of specimens with different PS content. 3.75 wt%, the elongation at the break of the specimens reaches a maximum of 0.5494, yet it is still less than the initial elongation at break of the specimens. The tensile stress-strain curves of the specimens doped with different weight fractions of PS are shown in Figure 9. Despite the different weight fractions of PS incorporated, the stress-strain curves of the specimens were linear, i.e., they only showed the elastic phase and did not show the damage phase, which was due to the influence of the environment [31].