Mechanical and fracture properties of injection molded thermoplastic polyester elastomers under thermo-oxidative degradations

초록

This study investigates the effects of injection speed on the mechanical properties and degradation behavior of thermoplastic polyester elastomers used in constant-velocity joint boots. The specimens were injection-molded under identical processing conditions, except for the injection speed, which was set to 15, 50, and 85 mm/s. Thermal aging was conducted at 120, 135, and 150 degrees C for 72, 336, and 720 h, respectively. The tensile and fracture properties before and after thermal aging were quantitatively evaluated through tensile and essential work of fracture tests. The degradation mechanism was examined using Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. Fracture surface morphology was characterized using scanning electron microscopy to analyze the crack propagation modes and changes in the plastic deformation zone with increasing temperature. Additionally, the property retention ratios for each injection speed were compared to evaluate thermal aging resistance, and an optimal injection speed was proposed.

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