where Δ𝑯𝒎 is the heat of fusion of each sample (J/g) and Δ𝑯𝒎’ is the heat of melting for 100% crystalline polystyrene, equal to 86 J/g [18].
The PS failure surface analysis was performed by observing the fracture cross-section after the test. This surface was examined using SEM (Quanta FEG250, FEI). The samples were previously coated with platinum in a vacuum chamber.
Results and Discussion
The investigation of the mechanical fatigue behavior of PS was carried out by maintaining the stress amplitude between 7.5–13 Mpa, at room temperature until material failure occurred, as observed in Figure 1.A. Figure 1.B shows the deformation response of the applied load.