Redesigned Hybrid Nylons with Optical Clarity and Chemical Recyclability

Robin Cywar, Nicholas Rorrer, Heather Mayes, Anjani Maurya, Christopher Tassone, Gregg Beckham, Eugene Chen

Research output: Contribution to journalArticlepeer-review

51 Scopus Citations


Aliphatic polyamides, or nylons, are typically highly crystalline and thermally robust polymers used in high-performance applications. Nylon 6, a high-ceiling-temperature (HCT) polyamide from ϵ-caprolactam, lacks expedient chemical recyclability, while low-ceiling temperature (LCT) nylon 4 from pyrrolidone exhibits complete chemical recyclability, but it is thermally unstable and not melt-processable. Here, we introduce a hybrid nylon, nylon 4/6, based on a bicyclic lactam composed of both HCT ϵ-caprolactam and LCT pyrrolidone motifs in a hybridized offspring structure. Hybrid nylon 4/6 overcomes trade-offs in (de)polymerizability and performance properties of the parent nylons, exhibiting both excellent polymerization and facile depolymerization characteristics. This stereoregular polyamide forms nanocrystalline domains, allowing optical clarity and high thermal stability, however, without displaying a melting transition before decomposition. Of a series of statistical copolymers comprising nylon 4/6 and nylon 4, a 50/50 copolymer achieves the greatest synergy in both reactivity and polymer properties of each homopolymer, offering an amorphous nylon with favorable properties, including optical clarity, a high glass transition temperature, melt processability, and full chemical recyclability.

Original languageAmerican English
Pages (from-to)5366-5376
Number of pages11
JournalJournal of the American Chemical Society
Issue number12
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

NREL Publication Number

  • NREL/JA-2A00-81806


  • chemical recyclability
  • circular nylon
  • hybrid monomer design
  • lactam
  • stereochemical control
  • stereoregular polymer


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