Recyclable, strong thermosets and organogels via paraformaldehyde condensation with diamines.
Nitrogen-based thermoset polymers have many industrial applications (for example, in composites), but are difficult to recycle or rework. We report a simple one-pot, low-temperature polycondensation between paraformaldehyde and 4,4'-oxydianiline (ODA) that forms hemiaminal dynamic covalent networks (HDCNs), which can further cyclize at high temperatures, producing poly(hexahydrotriazine)s (PHTs). Both materials are strong thermosetting polymers, and the PHTs exhibited very high Young's moduli (up to ~14.0 gigapascals and up to 20 gigapascals when reinforced with surface-treated carbon nanotubes), excellent solvent resistance, and resistance to environmental stress cracking. However, both HDCNs and PHTs could be digested at low pH (<2) to recover the bisaniline monomers. By simply using different diamine monomers, the HDCN- and PHT-forming reactions afford extremely versatile materials platforms. For example, when poly(ethylene glycol) (PEG) diamine monomers were used to form HDCNs, elastic organogels formed that exhibited self-healing properties.
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA. hedrick@us.ibm.com jmgarcia@us.ibm.com.
Jeannette M
JM
García
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
Gavin O
GO
Jones
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
Kumar
K
Virwani
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA. University of California, Berkeley, Department of Chemical and Biomolecular Engineering, 201 Gilman Hall, Berkeley, CA 94720, USA.
Bryan D
BD
McCloskey
IBM Tucson, 9000 South Rita Road, Tucson, AZ 85744, USA.
Dylan J
DJ
Boday
Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, Netherlands.
Gijs M
GM
ter Huurne
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
Hans W
HW
Horn
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
Daniel J
DJ
Coady
King Abdulaziz City for Science and Technology, Post Office Box 6086, Riyadh 11442, Saudi Arabia.
Abdulmalik M
AM
Bintaleb
King Abdulaziz City for Science and Technology, Post Office Box 6086, Riyadh 11442, Saudi Arabia.
Abdullah M S
AM
Alabdulrahman
King Abdulaziz City for Science and Technology, Post Office Box 6086, Riyadh 11442, Saudi Arabia.
Fares
F
Alsewailem
King Abdulaziz City for Science and Technology, Post Office Box 6086, Riyadh 11442, Saudi Arabia.
Hamid A A
HA
Almegren
IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA. hedrick@us.ibm.com jmgarcia@us.ibm.com.
James L
JL
Hedrick