## Materials and Methods
### Specim Preparation  
(1) Before experimenting, the PE80 PE pipes are required to be cut into rectangular samples strips by a punching machine, with at least 3 specimens in each group, and at least 3 groups of specimens are prepared. The cut samples need to be carefully rinsed with water to ensure that the surface is free of any impurities and then blotted dry with filter paper with good absorbency. After the water is drained, the appearance of the sample strip needs to be carefully inspected to ensure that there is no damage or deformation. If any problems are found, the specimen needs to be replaced in time to ensure the accuracy of the experimental results. The treated PE80 rectangular samples were then submerged in corrosion solutions containing, respectively, PH1, PH5, and PH8. During the seven days of specimen immersion, the container needed to be shaken once a day to ensure that the specimen is fully exposed to the corrosion solution. After seven days of immersion, the specimen needed to be removed from the corrosion solution, its surface rinsed with water, followed by filter paper to absorb the corrosion solution on the surface of the specimen, and then checked to see whether there was any change in the appearance of the specimen.  
(2) Using a Shimadzu AGS-X electronic universal testing equipment, a rectangular sample strip of sopped polyethylene material was cut into a dumbbell form following the ISO 1167-1:2006 [19] standard based on the thickness of the pipe and the standard of the specimen required for the experiment (Figure 2). The dumbbell-shaped specimen was completed by applying the cutter uniformly on the inner surface of the sample at room temperature [20]. During the punching process, the cutter needed to be kept perpendicular to the specimen to ensure that the size of the cutout specimen is accurate. The selection of the cutting tool is based on the thickness of the pipe to ensure the accuracy and reliability of the specimen. The shape and dimensions of the specimen are shown in Figure 3.  
The standard specimen size of each part is employed in this experiment for tensile tests and immersion acid and alkali corrosion investigations, as stated in Table 1. One of the crucial aspects of the experimental design that directly influences the validity and precision of the results is the size of the experimental sample. To replicate the potentially corrosive environment seen in actual use, the sample must be fully immersed in acid and alkali solutions during the experimental process. To minimize the sample's non-uniform deformation during stretching, uniform forces must be applied. We can guarantee the validity of the data collected under the experimental settings by precisely controlling the dimensions of the experimental samples. Understanding the mechanical characteristics of polyethylene materials after acid and alkaline corrosion and aging requires this.  
\begin{table}
\begin{tabular}{c c c} \hline
**Symbols** & **Description** & **Size** \\ \hline A & Minimum total length & 115 mm \\ B & End width & 25 mm \\ C & Parallel section length & 33 mm \\ D & Parallel section width & 6 mm \\ E & Small radius & 14 mm \\ F & Large radius & 25 mm \\ G & Distance between markers & 25 mm \\ H & Distance between wall & 80 mm \\  & thickness clamps & \\ \hline \end{tabular}
\end{table}
Table 1: Name and size of each part of the standard specimen.  
Figure 3: Standard specimen size chart.  
Figure 2: Shimadzu AGS-X type electronic.