Current Trends in Nanocomposite Foams

Abstract

This article presents a brief but concise review of the current research efforts on polymeric nanocomposite foams production, characterization, and applications. Survey indicates that the emergence of nanocomposites has resulted in the development of a new group of materials regarded as nanocomposite foams. Nanocomposites result from the use of nano-sized (10-09 m) particles as fillers to modify and enhance the properties of polymers and other matrices. The combination of functional nanoparticles and foaming technologies such as supercritical fluid foaming, chemical foaming, syntactic foaming, aerogel foaming, phase inversion foaming etc. generate these new materials regarded as nanocomposite foams that have light weight, high specific strength, and multifunctional attributes. Enhanced thermo-mechanical properties of nanocomposite foams result from improved cell morphology that is mainly attributable to the role of nanoparticles as nucleation agents for bubble generation. High-specific mechanical properties and multifunctional characteristics of nanocomposite foams make them cost-effective and desirable in a multitude of application areas including structural, energy-dissipating/absorbing, acoustical insulation, flammability resistance, and others. Of particular importance in this study of nanocomposite foams is the flammability resistance effect of nanoparticles. The intumescent model (NIST, NMAB, and others) indicates that the flame barrier mechanism involves a high-performance carbonaceous-silicate char; this char build-up insulates the underlying material. Understanding this char build-up mechanism presents a challenge and area of research interest in the effort to develop new generation foams that are suitable in energy absorbing materials and structures.

Low density polyethylene/silica nanocomposite foams. Relationship between chemical composition, particle dispersion, cellular structure and physical properties

“…The combination of foaming technologies and polymer nanocomposites can lead to a new class of multifunctional materials [1].…”

“…On the one hand, nanoparticles can modify and optimize the cellular structure and on the other hand, they are able of improving the morphology and properties of the solid polymer matrix comprising the cell walls [1,2].…”

“…Nanoparticles can contribute to obtain improved cellular structures because they act as nucleating agents and they can also modify the polymer rheology inducing strain hardening and thus, favoring gas retention during the foaming process [1][2][3][4]. Foams with reduced cell sizes and more uniform and narrower cell sizes distributions usually exhibit enhanced physical properties [5][6][7].…”

Mechanical response of polycarbonate nanocomposites to high velocity impact

“…As terrorist attacks have increased around the globe in recent years, the issue of combat survivability has become a primary concern for the public and governments [1][2][3][4][5]. Personal and vehicle protection from blast and ballistic impacts are more important to reduce life threatening situations to our soldiers, police force, and as well aid workers and other civilian personnel working in hostile areas.…”

“…Once soldiers are deployed from their protected vehicles, they require lightweight body protection that allows them to operate freely at high or low temperatures and altitudes whilst carrying a full battle load. These considerations have led to an increase in interest and activity levels in the homeland security, defence, and aerospace industries in the development of protection materials for applications of body armour and armed vehicles [3,4,6].…”