NMR Analysis to Identify Biuret Groups in Common Polyureas

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Abstract

Polyureas (PU) are well known as a class of high impact engineering materials, and widely used also in emerging advanced applications. As a general observation, most of them are only soluble in a very limited number of highly protonic solvents, which makes their chemical structure analysis a great challenge. Besides the presence of abundant hydrogen bonding, the poor solubility of PU in common organic solvents is often ascribed to the formation of biuret crosslinking in their molecular chains. To clarify the presence of biuret groups in PU has been of great interest. To this end, two samples, based on hexamethylene diisocyanate (HDI) and toluene diisocyanate (TDI) respectively, were synthesized by precipitation polymerization of each of these diisocyanates in water-acetone at 30 °C. Their chemical structures were analyzed by high resolution magic angle spinning (HR-MAS) NMR, and through comparison of their NMR spectra with those of specially prepared biuret-containing polyurea oligomers, it was concluded that biuret group was absent in all the PU prepared at 30 °C. In addition, this NMR analysis was also applied to a PU obtained by copolymerization of TDI with ethylene diamine (EDA) and water at 65 °C in EDA aqueous solution. It was confirmed that biuret unit was also absent in this PU and that EDA was more active than water towards TDI. The presence of EDA was crucial to the formation of uniform PU microspheres. This study provides therefore a reliable method for the analysis of PU chemical structure.

Keywords

Diisocyanate Polyurea Chemical structure Biuret NMR spectroscopy 

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Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (Nos. 21274054, 21304038 and 51473066), Research Foundation of University of Jinan (No. XKY1604) and by Science & Technology Development Plan of Shandong Province (No. 2017GGX202009), China.

References

  1. 1.
    Davidson, J. S.; Fisher, J. W.; Hammons, M. I.; Porter, J. R.; Dinan, R. J. Failure mechanisms of polymer-reinforced concrete masonry walls subjected to blast. J. Struct. Eng. 2005, 131(8), 1194–1205CrossRefGoogle Scholar
  2. 2.
    Mohotti, D.; Ngo, T.; Mendis, P.; Raman, S. N. Polyurea coated composite aluminium plates subjected to high velocity projectile impact. Mater. Design 2013, 52(24), 1–16CrossRefGoogle Scholar
  3. 3.
    Samiee, A.; Amirkhizi, A. V.; Nemat-Naser, S. Numerical study of the effect of polyurea on the performance of steel plates under blast loads. Mech. Mater. 2013, 64(9), 1–10CrossRefGoogle Scholar
  4. 4.
    Ley, S. V.; Mitchell, C.; Pears, D.; Ramarao, C.; Yu, J. Q.; Zhou, W. Recyclable polyurea microencapsulated Pd nanoparticles: An efficient catalyst for hydrogenolysis of epoxides. Org. Lett. 2003, 5(24), 4665–4668CrossRefGoogle Scholar
  5. 5.
    Han, H.; Zhou, Y.; Li, S.; Wang, Y.; Kong, X. Z. Immobilization of lipase from pseudomon as fluorescens on porous polyurea and its application in kinetic resolution of racemic 1-phenylethanol. ACS Appl. Mater. Interfaces 2016, 8(39), 25714–25724CrossRefGoogle Scholar
  6. 6.
    Jiang, X.; Yu, Y.; Li, X.; Kong, X. Z. High yield preparation of uniform polyurea microspheres through precipitation polymerization and their application as laccase immobilization support. Chem. Eng. J. 2017, 328, 1043–1050CrossRefGoogle Scholar
  7. 7.
    Jacquemond, M.; Jeckelmann, N.; Ouali, L.; Haefliger, O. P. Perfume-containing polyurea microcapsules with undetectable levels of free isocyanates. J. Appl. Polym. Sci. 2009, 114(5), 3074–3080CrossRefGoogle Scholar
  8. 8.
    Li, J.; Hughes, A. D.; Kalantar, T. H.; Drake, I. J.; Tucker, C. J.; Moore, J. S. Pickering-emulsion-templated encapsulation of a hydrophilic amine and its enhanced stability using poly(allyl amine). ACS Macro Lett. 2014, 3(10), 976–980CrossRefGoogle Scholar
  9. 9.
    Chen, L.; Xu, L.; Shang, H.; Zhang. Z. Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system. Energ. Convers. Manage. 2009, 50(3), 723–729CrossRefGoogle Scholar
  10. 10.
    Ying, H.; Zhang, Y.; Cheng, J. Dynamic urea bond for the design of reversible and self-healing polymers. Nat. Commun. 2014, 5, 3218CrossRefGoogle Scholar
  11. 11.
    Howarth, G. Polyurethanes, polyurethane dispersions and polyureas: Past, present and future. Surf. Coat. Int. Part B Coat. Trans. 2003, 86(2), 111–118CrossRefGoogle Scholar
  12. 12.
    Jiang, X.; Li, X.; Zhu, X.; Kong, X. Z. Preparation of highly uniform polyurea microspheres through precipitation polymerization and their characterization. Ind. Eng. Chem. Res. 2016, 55(44), 11528–11535CrossRefGoogle Scholar
  13. 13.
    Jiang, X.; Kong, X. Z.; Zhu, X. A Novel protocol for the preparation of uniform polymer microspheres with high yields through step polymerization of isophorone diisocyanate. J. Polym. Sci., Part A: Polym. Chem. 2011, 49(20), 4492–4497CrossRefGoogle Scholar
  14. 14.
    Sumi, M.; Chokki, Y.; Nakai, Y.; Nakabayashi, M.; Kanzawa, T. Studies on the structure of polyurethane elastomers. I. NMR spectra of the model compounds and some linear polyurethanes. Die Makromol. Chem. 1964, 78(1), 146–156Google Scholar
  15. 15.
    Chattopadhyay, D. K.; Raju, K. V. S. N. Structural engineering of polyurethane coatings for high performance applications. Prog. Polym. Sci. 2007, 32(3), 352–418CrossRefGoogle Scholar
  16. 16.
    Suzuoki, K.; Kagawa, K.; Fukuma, K.; Uda, B.; Ohmura, J. The analysis of synthetic and side reactions of polyurethaneurea. Nippon Gomu Kyokaishi 1999, 72, 139–143CrossRefGoogle Scholar
  17. 17.
    Mathisen, R. J.; Yoo, J. K.; Sung, C. S. P. Dye labeling technique for monitoring the cure of polyimides and polyureas: Model compound studies. Macromolecules 1987, 20(6), 1414–1416CrossRefGoogle Scholar
  18. 18.
    Okuto, H. Studies on the structure of polyurethane elastomers. II. High resolution NMR spectroscopic determination of allophanate and biuret linkages in the cured polyurethane elastomer: Degradation by amine. Die Makromol. Chem. 1966, 98(1), 148–163Google Scholar
  19. 19.
    Delebecq, E.; Pascault, J.; Boutevin, B.; Ganachaud, F. On the Versatility of urethane/urea bonds: Reversibility, blocked isocyanate, and non-isocyanate polyurethane. Chem. Rev. 2013, 113(1), 80–118CrossRefGoogle Scholar
  20. 20.
    Zhang, X.; Zhang, X. Y.; He, Y.; Chen, H. Progress in synthesis and characterization of HDI biuret. Pain Coat. Ind. 2011, 41(10), 71–75Google Scholar
  21. 21.
    Lapprand, A.; Boisson, F.; Delolme, F.; Mechin, F.; Pascault, J. P. Reactivity of isocyanates with urethanes: conditions for allophanate formation. Polym. Degrad. Stab. 2005, 90(2), 363–373CrossRefGoogle Scholar
  22. 22.
    Jiang, X.; Zhu, X.; Arnold, A. A.; Kong, X. Z.; Claverie, J. P. Polyurea structure characterization by HR-MAS NMR spectroscopy. Ind. Eng. Chem. Res. 2017, 56(11), 2993–2998CrossRefGoogle Scholar
  23. 23.
    Han, H.; Li, S.; Zhu, X.; Jiang, X.; Kong, X. Z. One step preparation of porous polyurea by reaction of toluene diisocyanate with water and its characterization. RSC Adv. 2014, 4(63), 33520–33529CrossRefGoogle Scholar
  24. 24.
    Jiang, X.; Zhu, X.; Kong, X. Z. A facile route to preparation of uniform polymer microspheres by quiescent polymerization with reactor standing still without any stirring. Chem. Eng. J. 2012, 213(12), 214–217CrossRefGoogle Scholar
  25. 25.
    Kong, X. Z.; Jiang, W.; Jiang, X.; Zhu, X. Preparation of coreshell and hollow polyurea microspheres via precipitation polymerization using polyamine as crosslinker monomer. Polym. Chem. 2013, 4(24), 5776–5784CrossRefGoogle Scholar
  26. 26.
    Li, S. S.; Han, H.; Zhu, X.; Jiang, X.; Kong, X. Z. Preparation and formation mechanism of porous polyurea by reaction of toluene diisocyanate with water and its Application as adsorbent for anionic dye removal. Chinese J. Polym. Sci. 2015, 33(8), 1196–1210CrossRefGoogle Scholar
  27. 27.
    Li, S.; Zhu, X.; Kong, X. Z.; Jiang, X. One step synthesis of porous polyurea by using TDI and EDA and its characterization. Acta Polymerica Sinica (in Chinese) 2016, (3), 391–398Google Scholar
  28. 28.
    Yang, Y.; Jiang, X.; Zhu, X.; Kong, X. Z. A facile pathway to polyurea nanofiber fabrication and polymer morphology control in copolymerization of oxydianiline and toluene diisocyanate in acetone. RSC Adv. 2015, 5(10), 7426–7432CrossRefGoogle Scholar
  29. 29.
    Alam, T. M.; Jenkins, J. E. "Advanced Aspects of Spectroscopy", Intech, Croatia, 2012, p. 279–301Google Scholar
  30. 30.
    Li, S.; Zhao, J.; Zhang, Z.; Zhang, J.; Yang, W. Aliphatic thermoplastic polyurethane-ureas and polyureas synthesized through a non-isocyanate route. RSC Adv. 2015, 5(9), 6843–6852CrossRefGoogle Scholar
  31. 31.
    Harris, R. F.; Kinney, J. E.; Savina, M. R.; Jeor, V. L. S.; Bicerano, J.; Durvasula, V. R.; Moreno, L. N. Synthesis and characterization of urea-based polyureas: 1. Urea-terminated poly(1,6-hexamethyleneurea) polyol dispersions. Polymer 1995, 36(22), 4275–4285Google Scholar
  32. 32.
    Edwards, P. A.; Striemer, G.; Webster, D. C. Synthesis, characterization and self-crosslinking of glycidyl carbamate functional resins. Prog. Org. Coat. 2006, 57(2), 128–139CrossRefGoogle Scholar
  33. 33.
    Wendisch, D.; Reiff, H.; Dieterich, D. Kernresonanzspektroskopische beiträge zur struktur und stereochemie von (cyclo)aliphatischen isocyanaten und deren folgeprodukten. Angew. Makromol. Chem. 1986, 141(1), 173–183CrossRefGoogle Scholar
  34. 34.
    Zhang, F.; Jiang, X.; Zhu, X.; Chen, Z.; Kong, X. Z. Preparation of uniform and porous polyurea microspheres of large size through interfacial polymerization of toluene diisocyanate in water solution of ethylene diamine. Chem. Eng. J. 2016, 303, 48–55CrossRefGoogle Scholar
  35. 35.
    Entelis, S. G.; Nesterov, O. V. Kinetics and mechanism of the reactions of isocyanates with compounds containing "active" hydrogen. Russ. Chem. Rev. 1966, 35(12), 917–930CrossRefGoogle Scholar
  36. 36.
    Lu, X.; Wang, Y.; Wu, X. Molecular interactions in polyurea by 1-D and 2-D NMR. Polymer 1993, 34(1), 56–60.CrossRefGoogle Scholar

Copyright information

© Chinese Chemical Society, Institute of Chemistry, Chinese Academy of Sciences and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.College of Chemistry and Chemical EngineeringUniversity of JinanJinanChina

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