Main chain polyaramides were prepared by the Highashi protocol from oxydianiline (ODA) and isophthalic acid (ISOPA) in the presence of 30-crown-10 and "60-crown-20". Relatively small amounts of the smaller macrocycle were incorporated (<2 mass %), but the larger one resulted in ∼17 mass % incorporation. These polymers display a previously observed irreversible high temperature exothermic transition that is attributed to a solid-state reorganization to intermolecularly hydrogen bonded amide pairs. An analogous set of polymers was prepared from bis(p-aminophenyl)fluorene (FLUODA) and ISOPA, with similar results, except that the exothermic transition was not observed. A main chain polypseudorotaxane was also prepared from Nylon-6,6 by condensation of adipoyl chloride and hexamethylene diamine in the presence of 30-crown-10; again only a small amount (∼5 mass %) of the macrocycle was threaded onto the backbone.
Lefebvre, H., Bheda, M., & Gibson, H. W. (2016). Main chain polyamide rotaxanes from aliphatic crown ethers. Polymer, 90, 317–330. https://doi.org/10.1016/j.polymer.2016.02.048