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The production of ordered mesoporous carbons (OMCs) can be achieved by direct pyrolysis of self-assembled polymers. Typically, these systems require a majority phase capable of producing carbon, and a minority phase to form pores through a thermal decomposition step. While polyacrylonitrile (PAN)-based block copolymers (BCPs) have been broadly reported as OMC precursors, these materials have a relatively narrow processing window for developing ordered nanostructures and often require sophisticated chemistry for BCP synthesis, followed by long crosslinking times at high temperatures. Alternatively, olefinic thermoplastic elastomers (TPEs) can be convered to large-pore OMCs after two steps of sulfonation-induced crosslinking and carbonization. Building on this platform, this work focuses on the precursor design concept for the efficient synthesis of OMCs through employing low-cost and widely available polystyrene-block-polybutadiene-block-polystyrene (SBS), which contains unsaturated bonds along the polymer backbone. As a result, the presence of alkene groups greatly enhances the kinetics of sulfonation-induced crosslinking reaction, which can be completed within only 20 min at 150 °C, nearly an order of magnitude faster than a recently reported TPE system containing a fully saturated polymer backbone. The crosslinking reaction enables the production of OMCs with pore sizes (∼9.5 nm) larger than most conventional soft-templating systems, while also doping sulfur heteroatoms into the carbon framework of the final products. This work demonstrates efficient synthesis of OMCs from TPE precursors which have a great potential for scaled production, and the resulting products may have broad applications such as for drug delivery and energy storage.
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This content will become publicly available on January 1, 2027
Pyrolysis and Pore Formation of Crosslinked Polystyrene‐ Block ‐Polybutadiene‐ Block ‐Polystyrene for Ordered Mesoporous Carbon Synthesis
ABSTRACT Thermoplastic elastomers (TPEs) have recently emerged as a class of promising precursors of ordered mesoporous carbons (OMCs) due to their low cost and broad availability. Despite understanding their reaction‐induced morphological changes, the fundamental pyrolysis kinetics of crosslinked TPEs remain poorly understood. In this study, we systematically investigate the pyrolysis behavior and pore formation mechanisms of sulfonated polystyrene‐block‐polybutadiene‐block‐polystyrene (SBS) using thermogravimetric analysis coupled with mass spectrometry (TGA‐MS), nitrogen physisorption measurements, and model‐free kinetic analysis. TGA‐MS results reveal a multi‐stage thermal decomposition process characterized by distinct thermal transitions and volatile product evolution. Nitrogen physisorption measurements demonstrate the development of mesoporosity and surface area with increasing pyrolysis temperature, identifying critical thermal windows for mesopore formation. Furthermore, kinetic modeling of the pyrolysis process was used to determine the apparent activation energies for the cleavage of aromatic and unsaturated moieties. These findings can provide important mechanistic insights for material and process design for producing OMCs via direct pyrolysis of commercially available TPEs.
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- Award ID(s):
- 2239408
- PAR ID:
- 10661379
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Polymer Science
- Volume:
- 64
- Issue:
- 1
- ISSN:
- 2642-4150
- Page Range / eLocation ID:
- 275 to 284
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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