تهيه و بررسي خواص مكانيكي، حرارتي و چسبندگي چسبهاي فيلمي پايه اپوكسي حاوي سيلسسكويي اكسان اوليگومري چندوجهي گليسيديل اتر دار و چقرمهكننده پلي(بوتيل آكريلات-بلاك- استايرن)

Preparation an‎d eva‎luation of mechanical, thermal an‎d adhesion properties of epoxy-based film adhesives modified with glycidyl ether Polyhedral Oligomeric Silsesquioxane Nanoparticles an‎d Poly (butyl acrylate-block-styrene) toughening agent

مهندسي شيمي

Glycidyl ether-containing polyhedral oligomeric silsesquioxane (GPOSS) nanoparticles are innovative nanoparticles used to enhance the mechanical an‎d thermal properties of epoxy resins. These nanoparticles consist of a silica cage an‎d glycidyl ether functional groups. The glycidyl ether functional groups exhibit excellent interaction with epoxy, making them a suitable choice for use in the formulation of structural adhesives based on epoxy. In this study, these reinforcing nanoparticles were used alongside a toughening agent, a block copolymer of poly(butyl acrylate-block-styrene). Additionally, a novolac-type phenolic resin was employed to improve the thermal stability of the epoxy resin. The effects of these nanoparticles an‎d the toughening agent on the mechanical, thermal, an‎d adhesive properties of the epoxy-based film adhesive were investigated. In this research, GPOSS nanoparticles were used in amounts of 1, 2, 3, an‎d 5 phr, an‎d the block copolymer toughening agent was used in amounts of 1, 2, 3, an‎d 5 phr in the formulation of the epoxy-based film adhesive. To eva‎luate the impact of these nanoparticles an‎d the toughening agent on the mechanical an‎d adhesive properties of the epoxy-based film adhesive, tensile tests, lap shear strength tests, an‎d peel strength tests were conducted. Subsequently, to assess the thermal stability of the epoxy-based film adhesive, thermogravimetric analysis (TGA) was performed on the dog-bone-shaped samples that exhibited the best mechanical properties in the tensile tests. Differential scanning calorimetry (DSC) was also used to study the curing process of the samples prepared at optimal levels. Furthermore, field emission scanning electron microscopy (FESEM) was employed to examine the dispersion of the nanoparticles an‎d toughening agent within the epoxy matrix an‎d to investigate the toughening mechanisms. Transmission electron microscopy (TEM) was also conducted to analyze the morphology of the GPOSS nanoparticles dispersed in toluene an‎d their dispersion in the epoxy, using an epoxy nanocomposite containing 2 phr of GPOSS nanoparticles. Finally, Fourier-transform infrared spectroscopy (FTIR) was used to study the bonds an‎d functional groups present. Based on the results obtained, the use of 2 phr of GPOSS nanoparticles an‎d 1 phr of the block copolymer toughening agent in the epoxy-based film adhesive formulation led to increases in tensile strength, modulus, toughness, shear strength, an‎d peel strength by 58.90%, 27.60%, 335.90%, 129, an‎d 201.82%, respectively, compared to the neat epoxy/novolac adhesive. Additionally, according to the TGA results, in the optimal sample containing 1 phr of the block copolymer an‎d 2 phr of GPOSS nanoparticles, the maximum degradation temperature increased by 3.18°C, an‎d the residual char content increased by 5.76%. Furthermore, based on the DSC results, the addition of GPOSS nanoparticles an‎d the block copolymer to the epoxy resin increased the reaction heat by 40% an‎d 33%, respectively. The simultaneous addition of both materials resulted in a 69% increase in the reaction heat.

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