Malleable and Recyclable Poly(urea-urethane) Thermosets bearing Hindered Urea Bonds

Yanfeng Zhang, Hanze Ying, Kevin R. Hart, Yuxiao Wu, Aaron J. Hsu, Anthony M. Coppola, Tae Ann Kim, Ke Yang, Nancy R. Sottos, Scott R. White, Jianjun Cheng

Research output: Contribution to journalArticle

Abstract

A new class of poly(urea-urethane) thermoset (PUU-TBAE) with dynamic hindered urea bonds (HUB) was developed. The shaped solid materials were processed using a Tetrahedron MTP-14 laboratory hot press in specific shaped aluminum moulds. Tensile experiments were performed on a custom-built, bidirectional screw-driven rail table. Nanoindentation measurements were performed using a Hysitron Triboindenter (TI-950) with a cube-corner probe of end radius ?50 nm. Glass-transition temperatures were tested by differential scanning calorimetry (DSC). Tensile tests of PUU-TBAE dog-bone samples were conducted according to ASTM D638. Type-V dog-bone samples were prepared via hot pressing in the aluminum mold. Tensile experiments were performed on a custom built bi-directional-screw-driven rail table that allows tensile testing of samples with both grips translating simultaneously and in opposite directions, keeping the center of mass of the sample stationary. This new thermoset has comparable mechanical properties and solvent resistance to conventional thermosets, but shows malleability under mild heating without the need of catalyst. Furthermore, the PUU-TBAE thermoset can be efficiently recycled, which avoids the use of energy-intensive degradation conditions and tedious monomer purification. Additionally, we showed that the PUU-TBAE thermoset can be easily sorted from a mixture of traditional thermoplastics and thermosets.

Original languageEnglish (US)
Pages (from-to)7646-7651
Number of pages6
JournalAdvanced Materials
Volume28
Issue number35
DOIs
StatePublished - Jan 1 2016

Keywords

  • dynamic covalent chemistry
  • hindered urea bonds
  • malleable
  • poly(urea-urethane) thermosets
  • recyclable

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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  • Cite this

    Zhang, Y., Ying, H., Hart, K. R., Wu, Y., Hsu, A. J., Coppola, A. M., Kim, T. A., Yang, K., Sottos, N. R., White, S. R., & Cheng, J. (2016). Malleable and Recyclable Poly(urea-urethane) Thermosets bearing Hindered Urea Bonds. Advanced Materials, 28(35), 7646-7651. https://doi.org/10.1002/adma.201601242