Chinese Journal of Polymer Science

, Volume 36, Issue 5, pp 655–664 | Cite as

Preparation of Poly(phosphoric acid piperazine) and Its Application as an Effective Flame Retardant for Epoxy Resin

Article
First Online:
Received:
Accepted:
  • 42 Downloads

Abstract

A phosphorus-nitrogen containing flame retardant additive of polyphosphoric acid piperazine, defined as PPAP, was synthesized by the salt-forming reaction between anhydrous piperazine and phosphoric acid, and the dehydration polymerization under heating in nitrogen atmosphere. Its chemical structure was well characterized by Fourier transform infrared (FTIR) spectroscopy, 13C and 31P solid-state nuclear magnetic resonance measurements. The synthesized PPAP and curing agent m-phenylenediamine were blended into epoxy resin (EP) to prepare flame retardant EP thermosets. The effects of PPAP on the fire retardancy and thermal degradation behavior of cured EP/PPAP composites were investigated by limiting oxygen index (LOI), vertical burning (UL-94), thermogravimetric analysis/infrared spectrometry (TG-IR) and cone calorimeter tests. The morphologies and chemical compositions of char residues for cured epoxy resin were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The results demonstrated that the flame retardant EP thermosets successfully passed UL-94 V-0 flammability rating and the LOI value was as high as 30.8% when incorporating 5wt% PPAP into the EP thermosets. The TGA results indicated that the synthesized PPAP flame retardant additive possessed high thermal stability and excellent charring capability. Meanwhile, the incorporation of PPAP stimulated the epoxy resin matrix to decompose and charring ahead of time due to its catalytic decomposition effect, which led to a higher char yield at high temperature. The morphological structures and the analysis results of XPS for char residues of EP thermosets revealed that the introduction of PPAP benefited the formation of a sufficient, more compact and homogeneous char layer containing phosphorus-nitrogen flame retardant elements on the material surface during combustion. The formed char layer with high quality effectively prevented the heat transmission and diffusion, limited the production of combustible gases, and inhibited the emission of smoke, leading to the reduction of heat and smoke release.

Keywords

Synthesis Polyphosphoric acid piperazine Flame retardant Epoxy resin thermosets Thermal degradation 
This is a preview of subscription content, log in to check access

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Notes

Acknowledgments

This work was financially supported by the Fundamental Research Funds for the Central Universities (No. 2572014EB06-02), the National Natural Science Foundation of China (No. 51673035) and Heilongjiang Major Research Projects (No. GA15A101).

References

  1. 1.
    Wang, X.; Song, L.; Xing, W. Y.; Lu, H. D.; Hu, Y. An effective flame retardant for epoxy resins based on poly(DOPO substituted dihydroxyl phenyl pentaerythritol diphosphonate). Mater. Chem. Phys. 2011, 125(3), 536–541.CrossRefGoogle Scholar
  2. 2.
    Chen, Z. K.; Yang, G.; Yang, J. P.; Fu, S. Y.; Ye, L.; Huang, Y. G. Simultaneously increasing cryogenic strength, ductility and impact resistance of epoxy resins modified by n-butyl glycidyl ether. Polymer 2009, 50(5), 1316–1323.CrossRefGoogle Scholar
  3. 3.
    Toldy, A.; Szabó, A.; Novák, C.; Madarász, J.; Tóth, A.; Marosi, G. MarosiIntrinsically flame retardant epoxy resin-fire performance and background-Part II. Polym. Degrad. Stab. 2008, 93(11), 2007–2013.CrossRefGoogle Scholar
  4. 4.
    Gao, M.; Wu, W. H.; Xu, Z. Q. Thermal degradation behaviors and flame retardancy of epoxy resins with novel silicon-containing flame retardant. J. Appl. Polym. Sci. 2013, 127(3), 1842–1847.CrossRefGoogle Scholar
  5. 5.
    Kandola, B. K.; Biswas, B.; Price, D.; Horrocks, A. R. Studies on the effect of different levels of toughener and flame retardants on thermal stability of epoxy resin. Polym. Degrad. Stab. 2010, 95(2), 144–153.CrossRefGoogle Scholar
  6. 6.
    Levchik, S. V.; Weil, E. D. A review of recent progress in phosphorus-based flame retardants. J. Fire Sci. 2006, 24(5), 345–364.CrossRefGoogle Scholar
  7. 7.
    Lin, H. T.; Lin, C. H.; Hu, Y. M.; Su, W. C. An approach to develop high-T g epoxy resins for halogen-freecopper clad laminates. Polymer 2009, 50(24), 5685–5692.CrossRefGoogle Scholar
  8. 8.
    Braun, U.; Balabanovich, A. I.; Schartel, B.; Knoll, U.; Artner, J.; Ciesielski, M.; Hoffmann, T. Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites. Polymer 2006, 47, 8495–8508.CrossRefGoogle Scholar
  9. 9.
    Ren, H.; Sun, J. Z.; Wu, B. J.; Zhou, Q. Y. Synthesis and properties of a phosphorus-containing flame retardant epoxy resin based on bis-phenoxy(3-hydroxy) phenyl phosphine oxide. Polym. Degrad. Stab. 2007, 92(6), 956–961.CrossRefGoogle Scholar
  10. 10.
    Li, Y.; Zheng, H. B.; Xu, M. J.; Li, B.; Lai, T. Synthesis of a novel phosphonate flame retardant and its application in epoxy resins. J. Appl. Polym. Sci. 2015, 132(45), 13085–13094.CrossRefGoogle Scholar
  11. 11.
    Xu, M. J.; Xu, G. R.; Leng, Y.; Li, B. Synthesis of a novel flame retardant based on cyclotriphosphazene and DOPO groups and its application in epoxy resins. Polym. Degrad. Stab. 2016, 123, 105–114.CrossRefGoogle Scholar
  12. 12.
    Xu, M. J.; Zhao, W.; Li, B. Synthesis of a novel curing agent containing organophosphorus and its application in flame-retarded epoxy resins. J. Appl. Polym. Sci. 2014, 131(23), 12406–12417.CrossRefGoogle Scholar
  13. 13.
    Martin, C.; Lligadas, G.; Ronda, J. C.; Galia, M.; Cadiz, V. Synthesis of novel boron-containing epoxy-novolac resins and properties of cured products. J. Polym. Sci., Part A: Polym. Chem. 2006, 44(21), 6332–6344.CrossRefGoogle Scholar
  14. 14.
    Dogan, M.; Unlu, S. M. Flame retardant effect of boron compounds on red phosphorus containing epoxy resins. Polym. Degrad. Stab. 2014, 99, 12–17.CrossRefGoogle Scholar
  15. 15.
    Zhang, T.; Liu, W.; Wang, M.; Liu, P.; Pan, Y.; Liu, D. Synthesis of a boron/nitrogen-containing compound based on triazine and boronic acid and its flame retardant effect on epoxy resin. High. Perform. Polym. 2016, DOI: 10.1177/0954008316650929.Google Scholar
  16. 16.
    Unlu, S. M.; Dogan, S. D.; Dogan, M. Comparative study of boron compounds and aluminum trihydroxide as flame retardant additives in epoxy resin. Polym. Adv. Technol. 2014, 25(8), 769–776.CrossRefGoogle Scholar
  17. 17.
    Canadell, J.; Mantecon, A.; Cadiz, V. Copolymerization of a silicon-containing spiroorthoester with a phosphorus-containing diglycidyl compound: influence on flame retardancy and shrinkage. Polym. Degrad. Stab. 2007, 92(10), 1934–1941.CrossRefGoogle Scholar
  18. 18.
    Mercado, L. A.; Galia, M.; Reina, J. A. Silicon-containing flame retardant epoxy resins: synthesis, characterization and properties. Polym. Degrad. Stab. 2006, 91(11), 2588–2594.CrossRefGoogle Scholar
  19. 19.
    Song, S.; Ma, J.; Cao, K.; Chang, G.; Huang, Y.; Yang, J. Synthesis of a novel dicyclic silicon-/phosphorus hybrid and its performance on flame retardancy of epoxy resin. Polym. Degrad. Stab. 2014, 99, 43–52.CrossRefGoogle Scholar
  20. 20.
    Qian, X.; Song, L.; Bihe, Y.; Yu, B.; Shi, Y.; Hu, Y.; Yuen, R. K. Organic/inorganic flame retardants containing phosphorus, nitrogen and silicon: preparation and their performance on the flame retardancy of epoxy resins as a novel intumescent flame retardant system. Mater. Chem. Phys. 2014, 143(3), 1243–1252.CrossRefGoogle Scholar
  21. 21.
    Wang, S.; Xin, F.; Chen, Y.; Qian, L.; Chen, Y. Phosphorus-nitrogen containing polymer wrapped carbon nanotubes and their flame-retardant effect on epoxy resin. Polym. Degrad. Stab. 2016, 129, 133–141.CrossRefGoogle Scholar
  22. 22.
    Zhang, X. H.; Liu, F.; Chen, S.; Qi, G. R. Novel flame retardant thermosets from nitrogen-containing and phosphoruscontaining epoxy resins cured with dicyandiamide. J. Appl. Polym. Sci. 2007, 106(4), 2391–2397.CrossRefGoogle Scholar
  23. 23.
    Gu, L.; Chen, G.; Yao, Y. Two novel phosphorus-nitrogencontaining halogen-free flame retardants of high performance for epoxy resin. Polym. Degrad. Stab. 2014, 108, 68–75.CrossRefGoogle Scholar
  24. 24.
    Artner, J.; Ciesielski, M.; Walter, O.; Doring, M.; Perez, R. M.; Sandler, J. K. W.; Altstadt, V.; Schartel, B. A novel DOPO-based diamine as hardener and flame retardant for epoxy resin systems. Macromol. Mater. Eng. 2008, 293(6), 503–514.CrossRefGoogle Scholar
  25. 25.
    Alcon, M. J.; Ribera, G.; Galia, M.; Cadiz, V. Advanced flame retardant epoxy resins from phosphorus-containing diol. J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 3510–3515.CrossRefGoogle Scholar
  26. 26.
    Lu, S. Y.; Hamerton, I. Recent developments in the chemistry of halogen-free flame retardant polymers. Prog. Polym. Sci. 2002, 27, 1661–1712.CrossRefGoogle Scholar
  27. 27.
    Duquesne, S.; Lefebvre, J.; Seeley, G.; Camino, G.; Delobel, R.; Lebras, M. Vinyl acetate/butyl acrylate copolymers: Part 2: fire retardancy using phosphorus-containing additives and monomers. Polym. Degrad. Stab. 2004, 85(2), 883–892.CrossRefGoogle Scholar
  28. 28.
    Perret, B.; Schartel, B.; Stöß, K.; Ciesielski, M.; Diederichs, J.; Döring, M.; Krämer, J.; Altstädt, V. A new halogen-free flame retardant based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide for epoxy resins and their carbon fiber composites for the automotive and aviation industries. Macromol. Mater. Eng. 2011, 296, 14–30.CrossRefGoogle Scholar
  29. 29.
    Yang, S.; Wang, J.; Huo, S.; Wang, M.; Tang, Y. Synthesis of a phosphorus/nitrogen-containing compound based on maleimide and cyclotriphosphazene and its flame-retardant mechanism on epoxy resin. Polym. Degrad. Stab. 2016, 126, 9–16.CrossRefGoogle Scholar
  30. 30.
    Yang, S.; Wang, J.; Huo, S.; Wang, M. Preparation and flame retardancy of a compounded epoxy resin system composed of phosphorus/nitrogen-containing active compounds. Polym. Degrad. Stab. 2015, 121, 398–406.CrossRefGoogle Scholar
  31. 31.
    Gao, M.; Yang, S. S. A novel intumescent flame-retardant epoxy resins system. J. Appl. Polym. Sci. 2010, 113(4), 2346–2351.CrossRefGoogle Scholar
  32. 32.
    Xu, M. J.; Ma, Y.; Hou, M. J.; Li, B. Synthesis of a cross-linked triazine phosphine polymer and its effect on fire retardancy, thermal degradation and moisture resistance of epoxy resins. Polym. Degrad. Stab. 2015, 119, 14–22.CrossRefGoogle Scholar
  33. 33.
    Yang, K.; Xu,, M. J.; Li, B. Synthesis of N-ethyl triazine-piperazine copolymer and flame retardancy and water resistance of intumescent flame retardant polypropylene. Polym. Degrad. Stab. 2013, 98(7), 1397–1406.CrossRefGoogle Scholar
  34. 34.
    Tan, Y.; Shao, Z. B.; Yu, L. X.; Long, J. W.; Qi, M.; Chen, L.; Wang, Y. Z. Piperazine-modified ammonium polyphosphate as monocomponent flame-retardant hardener for epoxy resin: flame retardance, curing behavior and mechanical property. Polym. Chem. 2016, 7(17), 3003–3012.CrossRefGoogle Scholar
  35. 35.
    Nguyen, T. M.; Chang, S. C.; Condon, B.; Thomas, T. P.; Azadi, P. Thermal decomposition reactions of cotton fabric treated with piperazine-phosphonates derivatives as a flame retardant. J. Anal. Appl. Pyrolysis. 2014, 110, 122–129.CrossRefGoogle Scholar
  36. 36.
    Gao, M.; Wo, Y. Q.; Wu, W. H. Microencapsulation of intumescent flame-retardant agent and application to epoxy resins. J. Appl. Polym. Sci. 2011, 119, 2025–2030.CrossRefGoogle Scholar
  37. 37.
    Gao, L. P.; Wang, D. Y.; Wang, Y. Z. A flame-retardant epoxy resin based on a reactive phosphorus-containing monomer of DODPP and its thermal and flame-retardant properties. Polym. Degrad. Stab. 2008, 93(7), 1308–1315.CrossRefGoogle Scholar
  38. 38.
    Zhang, W.; Li, X.; Yang, R. J. Pyrolysis and fire behaviour of epoxy resin composites based on a phosphorus-containing polyhedral oligomeric silsesquioxane (DOPO-POSS). Polym. Degrad. Stab. 2011, 96(10), 1821–1832.CrossRefGoogle Scholar
  39. 39.
    Yang, S.; Wang, J.; Huo, S. Q.; Wang, M.; Zhang, B. Synergistic flame-retardant effect of expandable graphite and phosphorus-containing compounds for epoxy resin: strong bonding of different carbon residues. Polym. Degrad. Stab. 2016, 128, 89–98.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.Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of ScienceNortheast Forestry UniversityHarbinChina

Personalised recommendations