EFFECT OF ALUMINA PARTICLE SIZE ON THE MECHANICAL PROPERTIES AND MORPHOLOGY OF PHENOLIC/GLASS FIBER REINFORCED COMPOSITES

In this study invesigated the effects of nano-sized (nAl₂O₃) and micro-sized (µAl₂O₃) aluminum oxide particles on the mechanical properties and morphology of phenolic resin-based glass fiber-reinforced composites were investigated. Experimental results indicated that both types of additives enhanced thermal conductivity and reduced material porosity after curing. Additionally, mechanical properties such as tensile strength, tensile modulus, flexural strength, fiber–matrix interfacial strength, and interlaminar shear strength were all improved. Notably, the composite containing 2% nAl₂O₃ exhibited the highest tensile strength (324.6 MPa), while 6% nAl₂O₃ yielded the greatest fiber–matrix bond strength (6.21 MPa), both outperforming µAl₂O₃-modified samples. In contrast, the incorporated µAl₂O₃ composites showed superior enhancements in tensile modulus, flexural strength, and especially interlaminar shear strength, with a peak value reaching up to 35.7 MPa, a 182% increase compared to the unmodified sample. These findings highlighted the potential of utilizing alumina particles with a various size to effectively enhance the mechanical performance of phenolic resin-based fiber-reinforced composites