چكيده به لاتين
The present study was conducted to characterize the mechanical properties of intrinsic self-healing polymer based on the Diels-Alder heat reversible reaction (DA). To this aim, a polymer-based on chemical groups capable of performing the Diels-Alder reaction was synthesized, and to enhance its mechanical properties, self-healing agents were combined with different percentages of a hot-cure epoxy resin. The differential scanning calorimetry analysis was also performed on the Diels-Alder bonding agents and the cured polymer to determine the Diels-Alder exothermic reaction and the retro Diels-Alder endothermic reaction temperatures.
Moreover, the design of experiment method (DOE) was used to find the number of required tests to investigate the effects of different parameters including various ratios of self-healing and epoxy resins, the time elapsed since fabrication, self-healing temperature, and the pressure of the self-healing process on the mechanical and self-healing properties of the material. Afterward, according to the designed test conditions, the glassfibers/synthesized self-healing polymer composite specimens were fabricated for three-point bending mechanical tests. To investigate the influence of the self-healing effect on the matrix cracks of fabricated composites, the [90(3)/0/90(3)] stacking sequence was selected and their flexural strength and modulus of elasticity were obtained. Consequently, the flexural strength and elastic modulus of the damaged and healed specimens were obtained by applying the tensile force on them and the respective self-healing efficiencies were calculated.
By determining the effects of different parameters on the flexural modulus and self-healing efficiency of the flexural modulus by using the factorial and Taguchi design methods, models were proposed to predict the magnitudes of the flexural modulus and self-healing efficiency of the flexural modulus. By using these models, the values of effective parameters to optimize mechanical and self-healing properties were determined. Accordingly, to achieve 100% self-healing efficiency, the maximum bending modulus available is 4.71 GPa, which is possible in a mixture of 54.03% of self-healing resin and the time of 10 days, at the temperature of 125°C and a pressure of 4.5 kPa.
