TY - JOUR
T1 - Transforming Polybutadiene with Tetrazine Click Chemistry into Antioxidant Foams That Fluoresce with Oxidation
AU - Bagge, Robb E.
AU - Mauldin, Timothy C.
AU - Boday, Dylan J.
AU - Kobilka, Brandon M.
AU - Loy, Douglas A.
N1 - Funding Information:
The authors would like to thank Brian Cherry for providing the excellent solid state NMR spectra, Tech Launch Arizona and the ACS Petroleum Research Fund (Grant 50941-ND7) for funding, and the IBM Ph.D Fellowship program.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/9/26
Y1 - 2017/9/26
N2 - The extent to which oxidative degradation of macromolecules can be delayed is generally limited by the low solubility of antioxidants in most polymers. This can be surmounted by synthesizing macromolecules with covalently attached antioxidant functionalities, but these are frequently expensive. Here, we demonstrate a simple click modification of polybutadienes (PDB) with 3,6-dichloro-1,2,4,5-tetrazine (DCT) that, in addition to modifying and stiffening the polymer chains, releases nitrogen gas to foam the solidifying polymers and generates dihydropyridazine groups that transform them into macromolecular antioxidants. Tetrazines react by a cycloaddition/cycloreversion reaction (Carboni-Lindsey reaction) with the C=C bonds to install 1,4-dihydropyridazine groups that increase the mass and rigidity of the butadiene macromolecules. The 1,4-dihydropyridazine group is an effective antioxidant that donates two hydrogen atoms per ring to combine with radicals and forms an aromatic pyridazine ring whose white fluorescence under UV permits visual monitoring of oxidation. Foams made by reacting liquid hydroxyl-terminated polybutadienes with DCT stabilize with thermoset formation through substitution reactions between the hydroxyl and dichlorodihydropyridazine groups.
AB - The extent to which oxidative degradation of macromolecules can be delayed is generally limited by the low solubility of antioxidants in most polymers. This can be surmounted by synthesizing macromolecules with covalently attached antioxidant functionalities, but these are frequently expensive. Here, we demonstrate a simple click modification of polybutadienes (PDB) with 3,6-dichloro-1,2,4,5-tetrazine (DCT) that, in addition to modifying and stiffening the polymer chains, releases nitrogen gas to foam the solidifying polymers and generates dihydropyridazine groups that transform them into macromolecular antioxidants. Tetrazines react by a cycloaddition/cycloreversion reaction (Carboni-Lindsey reaction) with the C=C bonds to install 1,4-dihydropyridazine groups that increase the mass and rigidity of the butadiene macromolecules. The 1,4-dihydropyridazine group is an effective antioxidant that donates two hydrogen atoms per ring to combine with radicals and forms an aromatic pyridazine ring whose white fluorescence under UV permits visual monitoring of oxidation. Foams made by reacting liquid hydroxyl-terminated polybutadienes with DCT stabilize with thermoset formation through substitution reactions between the hydroxyl and dichlorodihydropyridazine groups.
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U2 - 10.1021/acs.chemmater.7b02973
DO - 10.1021/acs.chemmater.7b02973
M3 - Article
AN - SCOPUS:85029942773
SN - 0897-4756
VL - 29
SP - 7953
EP - 7960
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 18
ER -