Highly advanced phthalonitrile composites from epoxy-ended hyperbranched poly(trimellitic anhydride ethylene glycol) ester grafted basalt fibers

摘要

In this study, a partially bio-based composite was prepared from a high-performance thermosetting resin, namely the phthalonitrile, and chopped basalt fibers (CBFs). Aiming to create strong covalent bonds between the matrix and the fillers, the CBFs were priorly grafted with an epoxy-ended hyperbranched poly (trimellitic anhydride ethylene glycol) ester (EHBP). The modification technique was validated by infrared spectroscopy and scanning electron microscopy (SEM). The effect of the fillers treatment on the mechanical performances highlighted remarkable enhancements in the tensile, bending, and Charpy impact properties. For instance, the tensile strength and modulus values were 30% and 20% higher than those afforded by the pristine fibers. Meanwhile, the SEM analysis of the fractured surfaces clearly confirmed the excellent state of adhesion and dispersion of the treated fillers with the polymeric matrix. Additionally, the influence of different quantities of EHBP-CBFs on the composite properties further revealed the exceptionally high mechanical properties of the developed materials. In fact, the tensile strength attained exceptional value of about 310 MPa for the composite of 20 wt% of EHBP-CBFs. Overall, this study unraveled the great potential of these newly developed materials with a focus on overcoming the debonding phenomena and easing the stress-transfer between the constituents.