Role of nanoparticles in microstructure tuning of toughened epoxy matrix synergism of viscoelastic and microwave absorption characteristics

Abstract

Epoxy resins are well established for a wide range of applications in coatings, adhesives, and fibre reinforced composites for aerospace and structural components. (Zhang et al. 2013) However, the foremost weaker side of epoxies is its brittleness (Zhang et al. 2018) or low fracture toughness due to its high degree of crosslink density that overtakes its excellent positive side. Several strategies were employed to modify the impact properties of epoxies. One among such common methods is the secondary phase inclusion of elastomers, thermoplastics, block copolymers, and nanoparticles. The toughening of epoxide with natural rubber depends on the structure and shape of rubber particles. It was also pointed out that the inter penetrating (IPN) or semi-interpenetrating (SIPN) network formed between epoxy and rubber combination boosts the mechanical properties to a significant extent. (Chen et al. 2011). Another important concern with epoxy is its intolerance to vibrations that often lead to undesirable properties such as unpleasant motions, noise, and dynamic stresses. These undesirable vibrations would lead to fatigue and failure of structures and ultimately decrease the reliability and performance of the resultant products. Hence, prevention of damping of these vibrations is very essential, which could be achieved either by passive or active mode. newlineCuring temperature plays a decisive role in tuning the toughness of the epoxy matrix. In practice, the mid temperature fast curing epoxy adhesives are in demand as extreme heat conditions deteriorate the peripheral components and the adherend. Secondly, throughput and energy can be increased if the driving cycle time decelerates from hours to several minutes. (Kamiya et al. 2016). Therefore, on considering these facts, fast curing powder epoxy adhesives were explored with hexamethylenetetramine (HMTA) as a curing newline