Skip to main content

Flame retardancy of an intumescent epoxy resin containing cyclotriphosphazene: experimental, computational and statistical studies


The current study is directed towards the evaluation of thermal stability and flame retardancy of the epoxy resin hexaglycidyl cyclotriphosphazene (HGCP) cured with 4,4′-methylene dianiline (MDA) and its polymer composite reinforced with bisphenol-A diglycidyl ether (DGEBA) by means of experimental, computational, and statistical approaches. The thermal properties of the polymer materials DGEBA-MDA (M1), HGCP-MDA (M2), and their mixture DGEBA-20%HGCP-MDA (M3) were evaluated using differential scanning calorimetry (DSC) and thermogravimetry–infrared spectroscopy (TG-FTIR) coupled analysis. The morphology was studied by scanning electron microscopy–energy dispersive X-ray analysis (SEM–EDX). The vertical flammability test was done used for the evaluation of the flame retardancy. The temperatures of exothermic peak (To) of the polymer materials M1, M2 and M3 were 95 °C, 77 °C and 93 °C, respectively. The results revealed that the addition of 20% of HGCP enhances the thermal stability compared to DGEBA and provides a DGEBA UL-94 V0 rating. SEM–EDX analysis showed that HGCP promotes the foaming and expansion of the coal as well as improved the gullies on the coal surface. Heteroskedasticity and autocorrelation consistent (HAC) covariance were performed to combine the results of the thermal degradation of the examined epoxy resins as a function of EHOMO and ELUMO, which were obtained from the optimized structure of the epoxy resins using the density functional theory. Consequently, the HAC model was validated by comparing the predicted theoretical results with experimental thermal degradation of the serial of compounds studied.

Graphic abstract

This is a preview of subscription content, access via your institution.

Scheme 1
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10


  1. 1.

    Dagdag O, Berisha A, Safi Z, Hamed O, Jodeh S, Verma C, Ebenso E, El Harfi A (2020) DGEBA-polyaminoamide as effective anti-corrosive material for 15CDV6 steel in NaCl medium: computational and experimental studies. J Appl Polym Sci 137:48402

    CAS  Article  Google Scholar 

  2. 2.

    Dagdag O, Essamri A, El Gana L, El Bouchti M, Hamed O, Cherkaoui O, Jodeh S, El Harfi A (2019) Synthesis, characterization and rheological properties of epoxy monomers derived from bifunctional aromatic amines. Polym Bull 76:4399–4413

    CAS  Article  Google Scholar 

  3. 3.

    Dagdag O, El Gana L, Hamed O, Jodeh S, El Harfi A (2019) Anticorrosive formulation based of the epoxy resin-polyaminoamide containing zinc phosphate inhibitive pigment applied on sulfo-tartaric anodized AA 7075–T6 in NaCl medium. J Bio- Tribo-Corros 5:25

    Article  Google Scholar 

  4. 4.

    Bekhta A, Elharfi A (2016) Comparative study of the rheological and thermal properties of the formol phenol novolac epoxy and those of the model resin diglycidylether of bisphenol A (DGEBA). Moroccan J Chem 4:61–67

    CAS  Google Scholar 

  5. 5.

    Jalila EA, El- Aouni N, El-Harfi A (2016) Synthesis, structural characterization by NMR and IR and rheological study of epoxy resin octafunctional. Moroc J Chem 4:2014–2023

    Google Scholar 

  6. 6.

    Li L, Cai Z (2020) Flame-retardant performance of transparent and tensile-strength-enhanced epoxy resins. Polymers 12:317

    CAS  Article  Google Scholar 

  7. 7.

    Song K, Wang Y, Ruan F, Liu J, Li N, Li X (2020) Effects of a macromolecule spirocyclic inflatable flame retardant on the thermal and flame retardant properties of epoxy resin. Polymers 12:132

    CAS  Article  Google Scholar 

  8. 8.

    Rane AV, Abitha V, Jadhava S (2020) Non-isocyanate polyurethane systems: a review. Moroc J Chem 8:8–4

    Google Scholar 

  9. 9.

    Huang R, Guo X, Ma S, Xie J, Xu J, Ma J (2020) Novel phosphorus-nitrogen-containing ionic liquid modified metal-organic framework as an effective flame retardant for epoxy resin. Polymers 12(1):108

    CAS  Article  Google Scholar 

  10. 10.

    Jadhav SA, Rane A, Abitha V, Suchithra P, Patil SS, Narute ST (2015) Polymeric particle board: a sustainable substitute to wooden boards. Moroc J Chem 3:2723–2729

    Google Scholar 

  11. 11.

    Lejeune N, Dez I, Jaffrès PA, Lohier JF, Madec PJ, de Oliveira S, Santos J (2008) Synthesis, crystal structure and thermal properties of phosphorylated cyclotriphosphazenes. Eur J Inorg Chem 2008:138–143

    Article  Google Scholar 

  12. 12.

    Krishnamurthy S, Sau A, Woods M (1978) Cyclophosphazenes. Adv Inorg Chem Radiochem 21:41–112

    CAS  Article  Google Scholar 

  13. 13.

    Allen CW (1991) Regio-and stereo-chemical control in substitution reactions of cyclophosphazenes. Chem Rev 91:119–135

    CAS  Article  Google Scholar 

  14. 14.

    Dagdag O, El Bachiri A, Hamed O, Haldhar R, Verma C, Ebenso E, El Gouri M (2021) Dendrimeric epoxy resins based on hexachlorocyclotriphosphazene as a reactive flame retardantpolymeric materials: a review. J Inorg Organomet Polym Mater 3:1–22

    Google Scholar 

  15. 15.

    Chang JY, Rhee SB, Cheong S, Yoon M (1992) Synthesis and thermal reaction of acetylenic group substituted poly (organophosphazenes) and cyclotriphosphazene. Macromolecules 25:2666–2670

    CAS  Article  Google Scholar 

  16. 16.

    Heyde M, Moens M, Van Vaeck L, Shakesheff KM, Davies MC, Schacht EH (2007) Synthesis and characterization of novel poly [(organo) phosphazenes] with cell-adhesive side groups. Biomacromol 8:1436–1445

    CAS  Article  Google Scholar 

  17. 17.

    Allcock HR, Austin PE (1981) Schiff base coupling of cyclic and high-polymeric phosphazenes to aldehydes and amines: chemotherapeutic models. Macromolecules 14:1616–1622

    CAS  Article  Google Scholar 

  18. 18.

    Levchik GF, Grigoriev YV, Balabanovich AI, Levchik SV, Klatt M (2000) Phosphorus-nitrogen containing fire retardants for poly (butylene terephthalate). Polym Int 49:1095–1100

    CAS  Article  Google Scholar 

  19. 19.

    Allen CW (1993) The use of phosphazenes as fire resistant materials. J Fire Sci 11:320–328

    CAS  Article  Google Scholar 

  20. 20.

    Gu JW, Zhang GC, Dong SL, Zhang QY, Kong J (2007) Study on preparation and fire-retardant mechanism analysis of intumescent flame-retardant coatings. Surf Coat Tech 201:7835–7841

    CAS  Article  Google Scholar 

  21. 21.

    Dagdag O, Hsissou R, Berisha A, Erramli H, Hamed O, Jodeh S, El Harfi A (2019) Polymeric-based epoxy cured with a polyaminoamide as an anticorrosive coating for aluminum 2024–T3 surface: experimental studies supported by computational modeling. J Bio- Tribo-Corros 5:58

    Article  Google Scholar 

  22. 22.

    Dagdag O, Hamed O, Erramli H, El Harfi A (2018) Anticorrosive performance approach combining an epoxy polyaminoamide-zinc phosphate coatings applied on sulfo-tartaric anodized aluminum alloy 5086. J Bio- Tribo- Corros 4:52

    Article  Google Scholar 

  23. 23.

    Dagdag O, Safi Z, Hamed O, Jodeh S, Wazzan N, Haldhar R, Safi SK, Berisha A, El Gouri M (2021) Comparative study of some epoxy polymers based on bisphenolic and aromatic diamines: synthesis, viscosity, thermal properties computational and statistical approaches. J Polym Res 28:1–16

    Article  Google Scholar 

  24. 24.

    Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA et al (2009) Gaussian 09 RA (2009), vol 121. Gaussian Inc, Wallingford, pp 150–166

    Google Scholar 

  25. 25.

    Cossi M, Barone V (1998) Analytical second derivatives of the free energy in solution by polarizable continuum models. J Chem Phys 109:6246–6254

    CAS  Article  Google Scholar 

  26. 26.

    Cammi R, Tomasi J (1995) Remarks on the use of the apparent surface charges (ASC) methods in solvation problems: iterative versus matrix-inversion procedures and the renormalization of the apparent charges. J Comput Chem 16:1449–1458

    CAS  Article  Google Scholar 

  27. 27.

    Cances E, Mennucci B, Tomasi J (1997) A new integral equation formalism for the polarizable continuum model: theoretical background and applications to isotropic and anisotropic dielectrics. J Chem Phys 107:3032–3041

    CAS  Article  Google Scholar 

  28. 28.

    Sastri V, Perumareddi J (1997) Molecular orbital theoretical studies of some organic corrosion inhibitors. Corrosion 53:617–622

    CAS  Article  Google Scholar 

  29. 29.

    Erdoğan Ş, Safi ZS, Kaya S, Işın DÖ, Guo L, Kaya C (2017) A computational study on corrosion inhibition performances of novel quinoline derivatives against the corrosion of iron. J Mol Struct 1134:751–761

    Article  Google Scholar 

  30. 30.

    Guo L, Safi ZS, Kaya S, Shi W, Tüzün B, Altunay N, Kaya C (2018) Anticorrosive effects of some thiophene derivatives against the corrosion of iron: a computational study. Front Chem 6:155

    Article  Google Scholar 

  31. 31.

    Parr RG, Donnelly RA, Levy M, Palke WE (1978) Electronegativity: the density functional viewpoint. J Chem Phys 68:3801–3807

    CAS  Article  Google Scholar 

  32. 32.

    Froimowit M (1993) HyperChem: a software package for computational chemistry and molecular modeling. Biotechniques 14:1010–1013

    Google Scholar 

Download references


NuhaWazzan and Zaki Safi gratefully acknowledge King Abdulaziz University’s High-Performance Computing Centre (Aziz Supercomputer) ( for assisting with the calculations for this study.

Author information



Corresponding authors

Correspondence to Omar Dagdag or Shehdeh Jodeh.

Ethics declarations

Conflict of interest

There are no conflicts to declare.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 20 KB)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Dagdag, O., El Gouri, M., Safi, Z.S. et al. Flame retardancy of an intumescent epoxy resin containing cyclotriphosphazene: experimental, computational and statistical studies. Iran Polym J 30, 1169–1179 (2021).

Download citation


  • Thermal stability
  • Thermal degradation
  • Flame retardancy
  • Epoxy resin
  • Composite
  • Computational and statistical approaches