Analysis of tensile failure mode and the mechanism dominated over polymer composite degradation

Despite previous research on the corrosion behavior of glass fiber reinforced polymer composites, the relationship between the degree of weakening of the resin/fiber interface bond and their mechanical properties is still necessary. In this research, empirical research is conducted to evaluate this issue. For this purpose, the polyester/glass samples were immersed in 10% HCl with three different temperatures of 25 °C, 50 °C and 70 °C, and changes in the mechanical properties of the samples and the apparent variations of the solution at time intervals of one up to four weeks are examined. The results showed that the ultimate tensile strength and Young modulus of composite specimens were reduced when placed in a solution with higher temperature or immersion time. Cracking caused by corrosion was shown in the resin/fiber interface using SEM photographs, and the degradation of the polyester resin was confirmed by observing the increase in surface cracks and changes in the solution color. Furthermore, visual inspection of sample failure surfaces after a tensile test showed that the failure occurred as DGM type. Finally, atomic absorption spectroscopy (AAS) analysis was performed to prove the occurrence of ion exchange mechanism. The results of this study indicate the occurrence of corrosion mechanisms in the interface area of composite specimens.