Scalable, low-density and flexible aerogels offer a unique combination of excellent mechanical properties and scalable manufacturability. Herein, we report the fabrication of a family of low-density, ambient-dried and hydrophobic poly(isocyanurate-urethane) aerogels derived from a triisocyanate precursor. The bulk densities ranged from 0.28 to 0.37 g cm-3 with porosities above 70% v/v. The aerogels exhibit a highly stretchable behavior with a rapid increase in the Young's modulus with bulk density (slope of log-log plot > 6.0). In addition, the aerogels are very compressible (more than 80% compressive strain) with high shape recovery rate (more than 80% recovery in 30 s). Under tension even at high strains (e.g., more than 100% tensile strain), the aerogels at lower densities do not display a significant lateral contraction and have a Poisson's ratio of only 0.22. Under dynamic conditions, the properties (e.g., complex moduli and dynamic stress-strain curves) are highly frequency- and rate-dependent, particularly in the Hopkinson pressure bar experiment where in comparison with quasi-static compression results, the properties such as mechanical strength were three orders of magnitude stiffer. The attained outcome of this work supports a basis on the understanding of the fundamental mechanical behavior of a scalable organic aerogel with potential in engineering applications including damping, energy absorption, and substrates for flexible devices.
S. Malakooti and S. Rostami and H. G. Churu and H. Luo and J. Clark and F. Casarez and O. Rettenmaier and S. Daryadel and M. Minary-Jolandan and L. Sotiriou-Leventis and N. Leventis and H. Lu, "Scalable, Hydrophobic and Highly-Stretchable Poly(isocyanurate-Urethane) Aerogels," RSC Advances, vol. 8, no. 38, pp. 21214-21223, Royal Society of Chemistry, Jun 2018.
The definitive version is available at https://doi.org/10.1039/c8ra03085e
Keywords and Phrases
Aerogels; Density (specific gravity); Dynamics; Elastic moduli; Esters; Hydrophobicity; Shape optimization; Stress-strain curves, Dynamic stress strains; Engineering applications; Hopkinson pressure bar; Lateral contraction; Mechanical behavior; Quasi-static compression; Shape recovery rate; Three orders of magnitude, Tensile strain
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Article - Journal
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01 Jun 2018