The objectives of this research article is to evaluate the mechanical and tribological properties of glass-fiber-reinforced epoxy (G-E) composites with and without graphite particulate filler. The laminates were fabricated by a dry hand layup technique. The mechanical properties, including tensile strength, tensile modulus, elongation at break, and surface hardness, were investigated in accordance with ASTM standards. From the experimental investigation, we found that the tensile strength and dimensional stability of the G-E composite increased with increasing graphite content. The effect of filler content (0-7.5 wt %) and sliding distance on the friction and wear behavior of the graphite-filled G-E composite systems were studied. Also, conventional weighing, determination of the coefficient of friction, and examination of the worn surface morphological features by scanning electron microscopy (SEM) were done. A marginal increase in the coefficient of friction with sliding distance for the unfilled composites was noticed, but a slight reduction was noticed for the graphite-filled composites. The 7.5% graphite-filled G-E composite showed a lower friction coefficient for the sliding distances used. The wear loss of the composites decreased with increasing weight fraction of graphite filler and increased with increasing sliding distance. Failure mechanisms of the worn surfaces of the filled composites were established with SEM.

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We report in this article the results of nanosilica (SiO 2 )-filled epoxy composites with different loadings and their electrical, thermal, mechanical, and free-volume properties characterized with different techniques. The morphological features were studied by transmission electron microscopy, and differential scanning calorimetry was used to investigate the glass-transition temperature (T g ) of the nanocomposites. The properties of the nanocomposites showed that the electrical resistivity (q), ultimate tensile strength, and hardness of the composites increased with SiO 2 weight fraction up to 10 wt % and decreased thereafter; this suggested that the beneficial properties occurred up to this weight fraction. The temperature and seawater aging had a negative influence on q; that is, q decreased with increases in the temperature and aging. The free-volume changes (microstructural) in the composite systems correlated with seawater aging but did not correlate so well with the mechanical properties.

Reinforcement of epoxy glass fabric composites with nano-and micro-fillers has resulted in the development of polymer composites with good electrical, thermal, and mechanical properties. The present work attempts to estimate the impact of hybrid fillers on dynamic-mechanical properties of the epoxy composites with a different filler. The dynamic mechanical parameters such as storage modulus, loss modulus, and damping factor over a temperature of 25 C-250 C have been investigated. The viscoelastic properties of composites are also confirmed with a Cole-Cole plot. From the results, the storage modulus of the composites is observed to lie in the range of 8000 to 12,500 MPa, and the epoxy composite with silicon carbide filler shows the highest storage modulus. Composite with 5 wt% of alumina shows the maximum loss modulus of 2100 MPa. The glass transition temperature of the base epoxy composite is 135 C and it increases to 137 C with the incorporation of hybrid cenosphere and molybdenum sulfide fillers. The storage modulus shows only marginal differences as compared to their counterparts with nanofillers but is higher by about 10-15% in comparison to the micron filler-based composites. However, the differences in the loss modulus of the nanocomposites, hybrid composites, and the composites with micron-sized filler are not significant.