Incorporation of nanoparticles in polymeric matrices to develop polymer nanocomposite with an idea to maximize the “nano-effect” derived out of the nanoparticles and to minimize the disadvantages of the polymer is an emerging area of research. Nanoparticles in the form of nanosheets, nanotubes, nanofibrils and quantum dots are incorporated in polymers to fabricate polymer nanocomposites, which possess tunable mechanical, thermal, electrical, magnetic and optical properties. However, to realize a quality composite, it is imperative to ensure that the selected nanoparticles are uniformly distributed within the matrix and have good compatibility with the matrix material. Thus, one should ensure strict control over the selection and operating parameters of the fabrication method of polymer nanocomposites. The paper presents a review of various fabrication techniques employed to obtain nanoparticle-filled polymer nanocomposites. An effort is also made to understand the effect of such nanoparticles on the mechanical and thermal properties of polymer nanocomposites.

In a multi-component system, the interfacial interactions between the various components trigger the behavior of the composite under external loading and thus determine the bulk properties of the material. In the present work, composite laminates made from TiO₂ modified epoxy reinforced with glass fiber are subjected to thermal loading and the effort is made to analyze the interfacial interactions through the experimental values of storage modulus, loss modulus and tan delta. The loading of TiO₂ nanoparticles in the epoxy resin is varied to also understand the effect of nanoparticle addition on the interfacial interactions through DMA. The addition of TiO₂ nanoparticles helped to increase the storage and loss modulus by improving the rigidity of the polymeric chain. To understand the effect of varying the loading of TiO₂ nanoparticles and to gauge the optimum wt.% addition of such nanoparticle, Tan delta, the degree of entanglement and the coefficient of the effectiveness of the nanofiller is found and the results indicate that the laminates successfully withstand the applied thermal load when the TiO₂ loading is kept at 2 wt.%. This optimum nanoparticle loading wt.% is further validated through the adhesion factor which is found with the help of Tan delta values.

Surface modified montmorillonite nanoclay created tortuous path to flow of moisture and enhanced bonding of PALF with epoxy, which resulted in lower diffusion coefficient and reduced impact of moisture diffusion in epoxy PALF nanoclay composites.

Tribological characterization using transmission electron microscope of precipitation hardened 7075 Aluminium alloy composites reinforced grey cast and white cast iron particle.

In the present work, a metal–matrix composite was casted using the LM13 aluminum alloy, which is most widely used for casting automotive components. Such applications require materials to withstand high operating temperatures and perform reliably without compromising their properties. In this regard, particulate-reinforced composites have gained widespread adaptability. The particulate reinforcements used comprise of one of the widely available industrial by-products. which is fly ash, along with the abundantly available quartz. Hybrid composites are fabricated through the economical liquid route that is widely used in mass production. Though there are numerous published research articles investigating the mechanical properties of metal–matrix composites, very few investigated the thermal properties of the composites. In the present work, thermal properties such as thermal conductivity and thermal diffusivity of cast hybrid composites were evaluated. The particulate reinforcements were added in varied weight percentages to the molten LM13 alloy and were dispersed uniformly using a power-driven stirrer. The melt with the dispersed particulate reinforcements was then poured into a thoroughly dried sand mold, and the melt was allowed to solidify. The quality of the castings was ascertained through density evaluation followed by a microstructural examination. It was found that the composites with only the fly ash particles as a reinforcement were less dense in comparison to the composites cast with the quartz particulate reinforcement. However, the hybrid composite, with both particulate reinforcements were dense. The microstructure revealed a refined grain structure. The thermal diffusivity and thermal conductivity values were lower for the composites cast with only the fly ash reinforcement. On the other hand, the composites cast with only quartz as the particulate reinforcement exhibited higher thermal diffusivity and thermal conductivity. The specific heat capacity was found to be lower for the fly ash-reinforced composites and higher for the quartz-reinforced composites in comparison to the LM13 base matrix alloy. However, the highest value of thermal diffusivity and thermal conductivity were reported for the hybrid composites with a 10 wt.% inclusion of both fly ash and quartz particulate reinforcements.

There have been continuous efforts to study the load response behavior of composites made from low-density and naturally available reinforcements for structural applications. In the current research, an effort is made to cast a hybrid composite with natural reinforcement having a greater density in comparison to the other. One of the research projects focused on here is to determine the saturation level of the quantity of reinforcements and their effect on the mechanical properties of the composite. The granite powder particles (GrP) (2 wt. % fixed) and the particles of silicon nitride (Si ₃ N ₄ ) (3, 6 and 9 wt.%) have been dispersed in Al7075 alloy by double step stir casting technique to produce the three categories of composites. Microstructure showed that as the quantity of reinforcements increased, the level of agglomeration and porosity increased proportionately. The alloy and all composites were peak-aged to determine the peak-aging time and its corresponding VHN. The materials were further homogenized and subjected to three-step aging according to the optimal conditions derived from previous research. The findings demonstrated that the composite's hardness improved with the total number of reinforcements, while exhibiting the highest level of hardness. However, the specific strength of some composites was superior than the other. Also, the composite with Si ₃ N ₄ 6% displayed the best wear characteristics at both lower and higher load conditions as compared to the alloy and composites. The captured micrographs correlated with the test results to justify this fact.