Compressive, hardness, and surface characterization of nanoclay-reinforced glass/epoxy laminates for structural applications

In this study, the effect of nanoclay reinforcement on the mechanical and surface performance of glass/epoxy laminated composites was comprehensively investigated with the aim of jointly evaluating compression behavior and surface properties, which have been addressed only to a limited extent in the literature. In particular, the study aimed to reveal the role of the nanoclay ratio in the compression strength-hardness-wettability balance and to determine the optimum reinforcement level. To this end, glass/epoxy laminates containing nanoclay at weight ratios of 0, 1, 3, and 5 wt% were produced, and the specimens were characterized using compression tests, microhardness measurements, contact angle analyses, atomic force microscopy (AFM), and scanning electron microscopy (SEM). The results obtained showed that the addition of nanoclay significantly affected both the structural integrity and surface behavior of the composites. According to experimental findings, a 3 wt% nanoclay content provided the most balanced performance, resulting in an approximate 19.4% increase in compressive strength and a 7.3% increase in hardness, while also improving surface wettability. AFM analyses confirmed a more homogeneous nanoparticle distribution and increased surface roughness at this ratio, while SEM images revealed strengthened fiber-matrix interfacial bonding and limited crack propagation. In contrast, particle agglomerations and microvoid formation were observed at a 5 wt% nanoclay content, leading to a partial decrease in mechanical performance. In conclusion, this study demonstrates that nanoclay reinforcement is a critical parameter that controls not only the mechanical strength but also the surface functionality of glass/epoxy composites, and provides a comprehensive assessment for determining the optimal nanoclay ratio for structural applications.