Keywords and Phrases
Pyrotechnique; Thermal Batteries
"Aerogels are nanoporous, low-density bulk objects, consisting of three-dimensional assemblies of nanoparticle. Structured similarly, polymeric aerogels are emerging as a mechanically strong alternative to traditional silica aerogels, which are fragile. Amongst polymeric aerogels, those based on polybenzoxazine (PBO - a type of phenolic resin), are extremely robust and comprise an economic alternative to resorcinol-formaldehyde aerogels, also a class of phenolic resins, as the main source of carbon aerogels. The drawback of the PBO chemistry has been the long (days) processing time at high-temperatures (>130 ºC). Herewith, we have developed an energy- and time-efficient process to PBO aerogels by inducing acid-catalyzed gelation at room-temperature completed in a few hours. The new aerogels are compared directly with their conventional counterparts and are found equivalent or better in terms of mechanical strength, thermal insulation value, surface area and carbonization yield. Hexahydrated iron chloride (FeCl₃.6H₂O) is a fairly strong Bronsted acid, which, based on the above, catalyzes formation interpenetrating networks of PBO and iron oxide nanoparticles (PBO-FeOx). Pyrolysis of that intimate mixture of a carbon source (PBO) and iron oxide undergoes smelting to highly porous (>90% v/v) monolithic metallic iron aerogels. The porous network was loaded with oxidizers (e.g., LiClO₄) into a new class of energetic materials (thermites, explosives, pyrotechnics). The PBO aerogels developed here comprise a wide-base platform for use as thermal insulators in civil and transportation applications (PBO aerogels themselves), electrodes for fuel cells, lithium ion batteries (nanoporous carbons), catalysts and energetic materials (PBO-FeOx)"--Abstract, page v.
Winiarz, Jeffrey G.
Dharani, Lokeswarappa R.
Ph. D. in Chemistry
Missouri University of Science and Technology. Department of Chemistry
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Polybenzoxazine aerogels I: High-yield room-temperature acid-catalyzed synthesis of robust monoliths, oxidative aromatization and conversion to microporous carbons
- Polybenzoxazine aerogels II: Interpenetrating networks with iron oxide and the carbothermal synthesis of highly porous monolithic pure iron(0) aerogels as energetic materials
xvi, 169 pages
© 2013 Shruti Mahadik-Khanolkar, All rights reserved.
Dissertation - Open Access
Library of Congress Subject Headings
Aerogels -- Mechanical properties
Chemical kinetics -- Effect of temperature on
Electronic OCLC #
Mahadik-Khanolkar, Shruti, "Polybenzoxazine aerogels: synthesis, characterization, conversion to porous carbons, and energetic composites" (2013). Doctoral Dissertations. 1821.