Abstract

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.

Department(s)

Chemistry

Comments

Support by NSF CMMI-1636306, CMMI-1661246, and CMMI-1726435, and Nashi-Tech New Materials, Inc. China is acknowledged. N. L. and C. S.-L. thank the Army Research Office under W911NF-14-1-0369.

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

International Standard Serial Number (ISSN)

2046-2069

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2018 Royal Society of Chemistry, All rights reserved.

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 License

Included in

Chemistry Commons

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