**7. Results and Discussion**

## *Mechanical Properties*

After aging for different times in the low-temperature air environment and lowtemperature water environment, the mechanical properties of the rubber waterstop are shown in Tables 1 and 2.

It can be seen from Tables 1 and 2, Figures 4 and 5 that the tensile strength, elongation, tear strength and compression permanent deformation of the rubber waterstop decreased in the low-temperature environment. Tensile strength and tear strength decreased by 34.9% and 24.7% in the low-temperature air environment. Tensile strength and tear strength decreased by 19.1% and 23.3% in the low-temperature water environment. This shows that the brittleness of rubber increases with the aging time, and the adverse effect is more obvious in the low-temperature air environment. The hardness increases slowly, the material becomes hard and gradually loses its elasticity. The decrease in compression permanent deformation indicates that the deformation capacity of vulcanized rubber gradually decreases with the increase in aging time at low temperature, that is, the plasticity

weakens. The reason for this is that the rubber main chain and side chain of the molecular chain and crosslinking chain fracture happens, simultaneously creating new crosslinking, whereas in the low-temperature environment, the rubber molecular chain is in a new crosslinking reaction, thus showing surface hardening after aging and brittle crack, namely due to its decreasing tensile strength, elongation, tear strength and compression permanent deformation.



**Table 2.** Mechanical properties of aging rubber waterstop in low-temperature water environment.


**Figure 4.** Compression set of waterstop in three different environments.

**Figure 5.** Tensile strength of waterstop in three different environments.
