Enhancement of Energy Absorption in Syntactic Foams by Nanoclay Incorporation for Sandwich Core Applications

Abstract

Syntactic foams are closed pore foams fabricated by the mechanical mixing of hollow glass particles in a matrix resin. The present study deals with change in compressive properties of syntactic foams due to the incorporation of nano-sized clay (nanoclay) particles. A surface modified clay, Nanomer I.30E, has been used in the fabrication of specimens. Six different types of syntactic foams are fabricated and tested for compressive properties. Three types of hollow particles (microballoons) of glass having different densities are used for fabrication. Each type of microballoon is combined with 0.02 and 0.05 volume fraction of nanoclay, respectively. The combined volume fraction of microballoons and nanocparticles is 0.65 in all kinds of foams. Compressive properties of these samples are compared with those of syntactic foams without nanoclay particles. It is observed that partial intercalation of nanoclay has taken place in the specimens and remaining nanoclay particles are present in small clusters. Such microstructure leads to nearly the same strength with considerable enhancement in fracture strain. Hence, the toughness of the material, measured as the area under stress-strain curve, is found to increase by 80-200% for various kinds of foams tested in the study. Fracture features of syntactic foams with and without nanoclay are compared.

Low velocity impact properties of nanoparticulate syntactic foams

“…reported the effect of nanoclay in syntactic foam [9,10]. However, these studies focus on quasi-static behavior.…”

Nanoclay reinforced thermoplastic toughened epoxy hybrid syntactic foam: Surface morphology, mechanical and thermo mechanical properties

“…It is also known that modulus, toughness and thermo mechanical properties of epoxy resin can be significantly enhanced by the addition of nanoclay [14][15][16][17][18][19]. Gupta and Maharsia [20] observed 80% and 125% increase in toughness, measured as area under the stress strain curves, for 2% and 5% nanoclay, respectively, in syntactic foam containing microballoons of density 220 kg/cm 3 . However, they observed a decrease in compressive strength by 10-20% by the incorporation of 2 vol% nanoclay, whereas 5% nanoclay has given nearly same level of strength.…”

Effect of nanoclay on the mechanical, dynamic mechanical and thermal properties of cyanate ester syntactic foams

“…This is attributed to the reinforcing effect of the nanoclay particles which improve the load bearing ability of the foam composites. Gupta and Maharsia also observed an improvement in compressive properties of epoxy syntactic foams with the addition of 5% nanoclay, whereas for the 2% nanoclay system, the compressive strength is lower than that for plain syntactic foam [7].…”

“…In nanoclay syntactic foams, flexural strength was observed to depend on the nanoclay volume fraction [6]. Gupta and Maharsia found that the toughness has improved by 80-200% by nanoclay reinforcement [7]. Maharsia et al claimed an increase in tensile strength upon the addition of nanoclay particles.…”