Flame Retardant Compounds for Epoxy Resins: A Review

Document Type : Review

Authors

1 Department of Composite, Faculty of Polymer Processing, Faculty of Petrochemical; Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran

2 Department of Composites Iran Polymer and Petrochemical Institute

3 Department of Adhesive and Resin, Faculty of Petrochemical; Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran

Abstract

Epoxy resins are widely used as encapsulating materials in the electronic and electrical industries, transportation, coatings, adhesives, and advanced composite matrices owing to their excellent heat, moisture and chemical resistance, high tensile strength, low shrinkage on curing, and excellent dimensional stability. Epoxy resins are very flammable; this nature seriously restricts their widespread applications, especially in the areas requiring high flame retardancy. To address this challenging problem, several approaches, such as use of halogen-based flame retardant, organophosphorus compounds (e.g., ammonium polyphosphate and melamine polyphosphate), inorganic flame retardants (most widely used alumina trihydrate and magnesium hydroxide known as ATH and MDH, respectively), nitrogen-based flame retardants, silicon-based flame retardants, intumescent flame retardants, and nanomaterials have been proposed. Phosphorus-containing compounds are mostly used as substitutes for the halogenated compounds in flame-retardant epoxy resins. Various phosphorus compounds are used as additive or reactive flame retardants. Comparing the additive flame retardants, reactive organophosphorus compounds present excellent flame retardant efficiency in the case of epoxy resins and it can be chemically linked to the backbone of the network either through being part of the curing agent or through the structure of epoxy resins itself and giving intrinsic flame retardancy. In this review, classification of flame retardants (halogen-based flame retardants, organophosphorus compounds, inorganic flame retardants, nitrogen- and silicon-based flame retardants, intumescent flame retardants and nanocomposites), the combustion cycle of polymers and application of flame retardants, especially phosphorus-based flame retardants for epoxy resins are introduced and classified. Experimental test methods for evaluation of flame retardancy like UL-94, limiting oxygen index and cone calorimeter are also discussed.

Keywords

References

  1. Levchik S.V. and Weil E.D., A Review of Recent Progress in Phosphorus-based Flame Retardants, J. Fire Sci., 24, 345-364, 2006.
  2. Veen I.V.D. and Boer J.D., Phosphorus Flame Retardants: Properties, Production, Environmental Occurrence, Toxicity and Analysis, Chemosphere, 88, 1119-1153, 2012.
  3. Choudhury A.K.R., Advances in Halogen-Free Flame Retardants, Tre. Text. Fashion Desig., 1, 70-74, 2018.
  4. Weil E.D., Levchik S.V., and Verlag C.H., Flame Retardants for Plastic and Textile: Practical Application, Elsevier, Munich, 2, 125-132, 2009.
  5. Schartel B., Phosphorus-based Flame Retardancy Mechanisms- Old Hat or a Starting Point for Future Development?, Materials, 3, 4710-4745, 2010.
  6. Barikani M., Askari F., Barikani M., and Barmar M., Effect of Fire Retardants in Improvement of Combustion Restriction and Thermal Decomposition of Polyurethane Foams: A Review, Iran. J. Polym. Sci. Technol. (Persian), 24, 3-31, 2011.
  7. Hull T.R., Witkowski A., and Hollingbery L., Fire Retardant Action of Mineral Fillers, Polym. Degr. Stab., 96, 1462­1469, 2011.
  8. Hollingbery L.A. and Hull T.R., The Fire Retardant Behaviour of Huntite and Hydromagnesite, Polym. Deg. Stab., 95, 2213-2225, 2010.
  9. Blyznyuk O., Vasilchenko A., Ruban A., and Bezuhla Y., Improvement of Fire Resistance of Polymeric Materials at Their Filling with Aluminosilicates, Mater. Sci. Forum, 1006, 55-61, 2020.
  10. Hollingbery L.A. and Hull T.R., The Thermal Decomposition of Natural Mixtures of Huntite and Hydromagnesite, hermochimica Acta, 528, 45-52, 2012.
  11. Khotbehsara M.M., Manalo A., Aravinthan T., Ferdous W., Nguyen K.T.Q., and Hota G., Ageing of Particulate-Filled Epoxy Resin under Hygrothermal Conditions, Constr. Buil. Mat., 249, 118846-118852, 2020.
  12. Zhou T., He X., Guo C., Yu J., Lu D., and Yang Q., Synthesis of a Novel Flame Retardant Phosphorus/Nitrogen/Siloxane and its Application on Cotton Fabrics, Text. Res. J., 85,  701-708, 2015.
  13. Li Z.S., Liu J.G., Song T., Shen D.X., and Yang S.Y., Synthesis and Characterization of Novel Phosphorous-Silicone-Nitrogen Flame Retardant and Evaluation of Its Flame Retardancy for Epoxy Thermosets, J. Appl. Polym Sci., 131, 40412, 2014.
  14. Bourbigot S., Turf T., Bellayer S.V., and Duquesne S., Polyhedral Oligomeric Silsesquioxane as Flame Retardant for Thermoplastic Polyurethane, Polym. DegStab., 94, 1230-1237, 2009.
  15. Xiao Y., Zheng Y., Wang X., Chen Z., and Xu Z., Preparation of a Chitosan-Based Flame-Retardant Synergist and Its Application in Flame-Retardant Polypropylene, J. Appl. Polym. Sci., 131, 40845, 2014.
  16. Bahreyni E., Farid M., Fakhari M.A., and Farid M., Ammonium Polyphosphate and Organically-Modified Montmorillonite Synergistic Effect on Flame-Retardant and Foaming Properties of High Density Polyethylene/Walnut Shell Powder Biocomposite, Iran. J. Polym. Sci. Technol. (Persian), 30, 299-310, 2017.
  17. Li G., Wang W., Cao S., Cao Y., and Wang J., Reactive, Intumescent, Halogen-Free Flame Retardant for Polypropylene,  J. Appl. Polym. Sci., 131, 40054, 2014.
  18. Wu D.H., Zhao P.H., Liu Y.Q., Liu X.Y., and Wang X.F., Halogen Free Flame Retardant Rigid Polyurethane Foam with a Novel Phosphorus-Nitrogen Intumescent Flame Retardant, J. Appl. Polym. Sci., 131, 39581, 2014.
  19. Gu L., Ge Z., Huang M., and Luo Y., Halogen-Free Flame-Retardant Waterborne Polyurethane with a Novel Cyclic Structure of Phosphorus-Nitrogen Synergistic Flame Retardant, J. Appl. Polym. Sci., 132, 41288, 2015.
  20. Ray S.S. and Okamoto M., Polymer/Layered Silicate Nanocomposites: A Review from Preparation to Processing, Prog. Polym Sci., 28, 1539-1641, 2003.
  21. Gilman J.W., Flammability and Thermal Stability Studies of Polymer Layered-Silicate (Clay) Nanocomposites, Appl. Clay Sci., 15, 31-49, 1999.
  22. Single P., Mehta R., and Upadhyay S.N., Clay Modification by the Use of Organic Cations, Green Sustainable Chem., 2, 21-25, 2012.
  23. Zhong Y., Wu W., Lin X., and Li M., Flame-Retarding Mechanism of Organically Modified Montmorillonite and Phosphorous-Nitrogen Flame Retardants for the Preparation of a Halogen-Free, Flame-Retarding Thermoplastic Poly(ester ether) Elastomer, J. Appl. Polym. Sci., 131, 41094, 2014.
  24. Bourbigot S., Duquesne S., and Jame C., Polymer Nanocomposites: How to Reach Low Flammability?, Macromolecular Symposia, 233, 180-190, 2006.
  25. Niazi M. and Beheshty M.H., A New Latent Accelerator and Study of Its Effect on Physical, Mechanical and Shelf-life of Carbon Fiber Epoxy Prepreg, Iran. Polym. J., 28, 337-346, 2019.
  26. Dareh M., Beheshty M.H., and Bazgir S., Effect of Type and Amount of Accelerator on Reactivity and Curing Behavior of Epoxy /Dicyandiamide/Accelerator System, Iran. J. Polym. Sci. Technol. (Persian), 33, 332-341, 2020.
  27. Khalina M., Beheshty M.H., and Salimi A., The Effect of Reactive Diluent on Mechanical Properties and Microstructure of Epoxy Resins, Polym. Bulletin, 76, 3905-3927, 2019.
  28. Liu X. and Liang B., Impact of a Novel Phosphorus-Nitrogen Flame Retardant Curing Agent on the Properties of Epoxy Resin, Mat. Res. Exp., 4, 1-24, 2017.
  29. Khalina M., Beheshty M.H., and Salimi A., Preparation and Characterization of DGEBA/EPN Epoxy Blends with Improved Fracture Toughness, Chinese J. Polym. Sci., 36, 632-640, 2018.
  30. Jamshidi H., Beheshty M.H., and Akbari R., Effect of CTBN Liquid Rubber and Flexible Diamine Curing Agent On Epoxy/Glass Prepregs Properties, J. Sci. Technol Compos. (Persian), 5, 25-32, 2018.
  31. Mozaffari S.M., Beheshty M.H., and Mirabedini S.M., Effect of Processing Conditions on the Microencapsulation of 1-Methylimidazole Curing Agent Using Solid Epoxy Resins, Iran. Polym. J., 26, 629-637, 2017.
  32. Mozaffari S.M. and Beheshty M.H., Nanoclay-Modified Microcapsules as a Latent Curing Agent in Epoxy, Polym. Bull., 78, 3103-3115, 2020.
  33. Ricciotti L., Roviello G., Tarallo O., Borbone F., Ferone C., Colangelo F., Catauro M., and Cioffi R., Synthesis and Characterizations of Melamine-Based Epoxy Resins, Molecular Sci., 14, 18200-18214, 2013.
  34. Mozaffari S.M. and Beheshty M.H., Thermally-Latent Curing Agents for Epoxy Resins: A Review, Iran. J. Polym. Sci. Technol. (Persian), 31, 409-426, 2019.
  35. Szolnoki B., Toldy A., Konrad P., Szebenyi G., and Marosi G., Comparison of Additive and Reactive Phosphorus-Based Flame Retardants in Epoxy Resins, Chem. Eng., 2, 85-91, 2013.
  36. Lu S. and Hamerton I., Recent Developments in the Chemistry of Halogen-Free Flame Retardant Polymers, Prog. Polym Sci., 27, 1661-1712, 2002.
  37. Aghdam T.R. and Shariatinia Z., Flame Retardancy in Polymeric Materials: A Short Overview, Basparesh (Persian), 7, 38-47, 2018.
  38. Aloshy B., Svetlana T.M., Malavika A., Paul J., and Jianping Z., Reactive and Additive Modifications of Styrenic Polymers with Phosphorus-Containing Compounds and Their Effects on Fire Retardance, Molecules, 25, 2020.
  39. Green J., Mechanisms for Flame Retardancy and Smoke Suppression: A Review, J. Fire Sci., 14, 426-442, 2014.
  40. Wang C.S., Berman J.R., Walker L.L., and Mendoza A., Meta-Bromobiphenol Epoxy Resins: Applications in Electronic Packaging and Printed Circuit Board, J. Appl. Polym. Sci., 43, 1315-1321, 1991.
  41. Lyon, R.E., and Castelli L.M., Flammability and Mechanical Properties of a New Fire Resistant Epoxy, Chem. Eng., 2, 267-279, 2001.
  42. Lu S.Y. and Hamerton I., Recent Developments in the Chemistry of Halogen-Free Flame Retardant Polymers, Prog. Polym Sci., 27, 1661-1712, 2002.
  43. Green J., A Review of Phosphorus-Containing Flame Retardants, J. Fire Sci., 14, 353-366, 1996.
  44. Levchik S.V., Camino G., Luda M.P., Costa L., Costes B., Henry Y., Muller G., and Morel E., Mechanistic Study of Thermal-Behavior and Combustion Performance of Epoxy Resins. II. TGDDM/DDS System, Polym Degr. Stab., 48, 359-370, 1995.
  45. Jain P., Choudhary V., and Varma I.K., Flame Retarding Epoxies with Phosphorus, Macromolecular Sci., 42, 139-183, 2007.
  46. Osada S., Asano E., Ino S., Aoki T., Tomiyoshi K., and Shiobara T., Semiconductor Encapsulating Epoxy Resin Composition and Semiconductor Device, US Pat., 6,291,556, 2001.
  47. Weil E.D. and Levchik S., A Review of Current Flame Retardant Systems for Epoxy Resins, Fire Sci., 22, 25.40, 2004. 
  48. Xiao W., He P., Hu G., and He B., Study on the Flame-Retardance and Thermal Stability of the Acid Anhydride-Cured Epoxy Resin Flame-Retarded by Triphenyl Phosphate and Hydrated Alumina, Fire Sci., 19, 369-377, 2001.
  49. Rosa A.D.L., Recca A., Carter J.T., and McGrail P.T., An Oxygen Index Evaluation of Flammability on Modified Epoxy/Polyester Systems, J. Appl. Polym Sci., 40, 4093-4098, 1999.
  50. Derouet D., Morvan F., and Brosse J.C., Chemical Modification of Epoxy Resins by Dialkyl (or aryl) Phosphates: Evaluation of Fire Behavior and Thermal Stability, J. Appl. Polym. Sci., 62, 1855-1868, 1996.
  51. Cong X., Fan L., Zhen D., Weilin X., Mengjiao Z., Kangjun X., Jifu D., and Long Z., Synthesis of 9,10-Dihydro-9-Oxa-10-Phosphaphenanthrene-10-Oxide Derivative Grafted Polyethylene Films for Improving the Flame Retardant and Anti-Dripping Properties, Polym Eng Sci., 60, 2804-2813, 2020.
  52. Ting T.G., Zhi W.L., Lai G.Y., and Zhi J.Z., Preparation of Zinc Hydroxystannate Nanocomposite Coated by Organophosphorus and Investigation of Its Effect on Mechanical Properties and Flame Retardancy of Poly(vinyl chloride), Royal Soc. Chem., 5, 99291-99298, 2015.
  53. Xiaodong Q., Lei S., Saihua J., Gang T., Weiyi X., Bibo W., Yuan H., and Richard K.K.Y., Novel Flame Retardants Containing 9,10-Dihydro-9-Oxa-10-Phosphaphenanthrene-10-Oxide and Unsaturated Bonds: Synthesis, Characterization, and Application in the Flame Retardancy of Epoxy Acrylates., Ind. Eng. Chem. Res., 52, 7307-7315, 2013.
  54. Joseph Z., David Y., Andrew P., Mayank P.S., Kali S., and Sergei L., Comparative Study of Reactive Flame Retardants Based on 9,10-Dihydro-9-Oxa-10-Phosphaphenanthrene 10-Oxide, J. Fire Sci., 35, 235-256, 2017.
  55. Liqiang G., Chen Q., Jianhui Q., Youwei Y., Eiichi S., and Liting Y., Preparation and Characterization of DOPO-Functionalized MWCNT and Its High Flame-Retardant Performance in Epoxy Nanocomposites, Polymers, 12, 613-626, 2020.
  56. Jelena V., Marija C. , Natasa C.K., Matic S., Ziga S., and Ivan J., Effect of Dfferent Flame-Retardant Bridged DOPO Derivatives on Properties of in Situ Produced Fiber-Forming Polyamide 6, Polymers, 12, 657-675, 2020. 
  57. Salmeia K.A. and Gaan S., An Overview of Some Recent Advances in DOPO-Derivatives: Chemistry and Flame Retardant Applications, Polym Degr. Stab., 113, 119-134, 2015.
  58. Wang C.S. and Lin C.H., Synthesis and Properties of Phosphorus-Containing Epoxy Resins by Novel Method, Polym. Sci., 37, 3903-3909, 1999.
  59. Wang C.S. and Shieh J.Y., Phosphorus-Containing Epoxy Resin for an Electronic Application, J. Appl. Polym Sci., 73, 353-361, 1999.
  60. Wang C.S. and Lin C.H., Synthesis and Properties of Phosphorus Containing Advanced Epoxy Resins, J. Appl. Polym Sci., 75, 429-436, 2000.
  61. Wang C.S. and Lee M.C., Synthesis and Properties of Epoxy Resins Containing 2-(6-Oxid-6H-Dibenz (c,e)(1,2) Oxaphosphorin-6-yl) 1,4-Benzenediol (II), Polymer, 41, 3631-3638, 2000.
  62. Lin C.H., Wu C.Y., and Wang C.S., Synthesis and Properties of Phosphorus-Containing Advanced Epoxy Resins. II, J. Appl. Polym Sci., 78, 228-235, 2000.
  63. Xiong Y.Q., Zhang X.Y., Liu J., Li M.M., Guo F., Xia X.N., and Xu W.J., Synthesis of Novel Phosphorus-Containing Epoxy Hardeners and Thermal Stability and Flame-Retardant Properties of Cured Products, J. Appl. Polym. Sci., 125, 1219–1225, 2012.
  64. Jeng R.J., Shau S.M., Lin J.J., Su W.C, and Chiu Y.S., Flame Retardant Epoxy Polymers Based on all Phosphorus-Containing Components, Polymer, 38, 683-693, 2002.
  65. Cho C.S., Fu S.C., Chen L.W., and Wu T.R., Aryl Phosphinate Anhydride Curing for Flame Retardant Epoxy Networks, Polym Int., 47, 203-209, 1998.
  66. Wang C.S. and Lin C.H., Properties and Curing Kinetic of Diglycidyl Ether of Bisphenol A Cured with a Phosphorus-Containing Diamine, J. Appl. Polym Sci., 74, 1635-1645, 1999.
  67. Chiu J.S., Jiang M.D., and Liu Y.L., Phosphorus-Containing Compounds and Their Use in Flame Retardance, US Pat., 6,441,067, 2002.
  68. Varma I.K. and Gupta U., Curing of Epoxy Resin with Phosphorylated Diamine, Macromol. Sci., 23, 19-36, 2006.
  69. Kuo P.L., Wang J.S., Chen P.C., and Chen L.W., Tailor-Made Thermal Stability Epoxy Curing Agents Containing Difunctional Phosphoric Amide Groups, Macromol. Chem. Phy., 202, 2175-2180, 2001.
  70. Jeng R.J., Wang J.R., Lin J.J., Liu Y.L., Chiu Y.S., and Su W.C., Flame Retardant Epoxy Polymers Using Phosphorus-Containing Polyalkylene Amines as Curing Agents, J. Appl. Polym. Sci., 82, 3526-3538, 2001.
  71. Ito M. and Miyake S., Flame-Retardant Resin Composition and Semiconductor Sealant 70 the Same, US Pat., 6,180,695, 2001.
  72. Liu X. and Liang B., Impact of a Novel Phosphorus-Nitrogen Flame Retardant Curing Agent on the Properties of Epoxy Resin, Mater. Res. Express, 4, 125103, 2017.
  73. Xu Y.J., Wang J., Tan Y., Qi M., Chen L., and Wang Y.Z., A Novel and Feasible Approach for One-Pack Flame-Retardant Epoxy Resin with Long Pot Life and Fast Curing, Chem. Eng. J., 337, 30-39, 2018.
  74. Guo X., Wang H., Ma D., He J., and Lei Z., Synthesis of a Novel, Multifunctional Inorganic Curing Agent and its Effect on the Flame-Retardant and Mechanical Properties of Intrinsically Flame Retardant Epoxy Resin, J. Appl. Polym. Sci., 135, 46410, 2018.
  75. Xu M., Zhao W., and Li B., Synthesis of a Novel Curing Agent Containing Organophosphorus and its Application in Flame-Retarded Epoxy Resins, J. Appl. Polym. Sci., 131, 41159, 2014.
  76. Wu X., Dong C., Wirasaputra A., Huang H., Liu S., Zhao J., and Fu Y., Imparting high Flame Retardancy to Epoxy Resin with Ultra-Low Loading of 5,10-Dihydro-Phenophosphazine-10-Oxide Functioned Triazine, High Perform. Polym., 30, 742-751, 2017.
  77. Kamalipour J., Beheshty M.H, Zohurianmehr M.J., Synthesis and Preliminary of New Phosphorous-Containing Flame-Retardant Hardeners for Epoxy Resin, 14th International Seminar on Polymer Science and Technology, Tarbiatmodares University, Tehran, Iran,
    1-12 November, 2020.
  78. Fathizadeh M.A. and Beheshty M.H., A Comparative Study on the Thermal Resistance, Flammability and Mechanical Properties of Unsaturated Polyester and Epoxy Resins, Iran. J. Polym. Sci. Technol. (Persian), 28, 409-419, 2016.
  79. Kiliaris P. and Papaspyrides C.D., Polymer/Layered Silicate (Clay) Nanocomposites: An Overview of Flame Retardancy, Prog. Polym. Sci., 35, 902-958, 2010.
  80. Debes B., Aruna S., and Nam K.K., Multifunctionality of Polymer Composites Challenges and New Solutions, Elsevier, 1, 102-143, 2015.
  81. Oisik D., Nam K.K., Mikael S.H., and Debes B., Durability and Life Prediction in Biocomposites, Fibre-Reinforced Composites and Hybrid Composites, Woodhead Publishing Series in Composites Science and Engineering, 1, 335-365, 2019.
  82. Dewaghe C., Lew C.Y., Claes M., and Nanocyl S.A., Polymer-Carbon Nanotube Composites Preparation, Properties and Applications, Woodhead Publishing Series in Composites Science and Engineering, 1, 718-745, 2011.
  83. Standard Test Method for Rate of Burning and/or Extent and Time of Burning of Plastics in a Horizontal Position, Annual Book of ASTM Standard, 08.01, D 635-18, 2018.
  84. Standard Test Method for Measuring the Comparative Burning Characteristics of Solid Plastics in a Vertical Position, Annual Book of ASTM Standard, 08.02, D 3801-20a, 2018.
  85. Standard Test Method for Measuring the Minimum Oxygen Concentration to Support Candle-Like Combustion of Plastics (Oxygen Index), Annual Book of ASTM Standard, 08.01, D 2863-19, 2017.
  86. Plastics-Determination of Burning Behaviour by Oxygen Index- Part 2: Ambient-Temperature Test, ISO 4589-2, 2017.
  87. Beata A. and Dawid J., Flame Retardants of Polymeric Materials –Calculation of the Oxygen Index, Technical Transactions, 9, 57-66, 2018.
  88. Miriam T.L. Ana M.S., Aranzazu M., Asuncion M., Felix C.G., and Jose M.G., Heteroaromatic Polyamides with Improved Thermal and Mechanical Properties, Polymers, 12, 1793, 2020.
  89. Naveen J.A., Mohammad J., and Naheed S., Sustainable Composites for Aerospace Applications, Woodhead Publishing Series in Composites Science and Engineering, 1, 109-123, 2018.
  90. Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter, Annual Book of ASTM Standard, 04.07, E 1354-17, 2018.
  91. Reaction-to-Fire Tests-Heat Release, Smoke Production and Mass Loss Rate - Part 5: Heat Release Rate (Cone Calorimeter Method) and Smoke Production Rate (Dynamic Measurement) under Reduced Oxygen Atmospheres, ISO/TS 5660-5, 2020.
  92. Standard Test Method for Determining the Heat Release Rate of Upholstered Furniture and Mattress Components or Composites Using a Bench Scale Oxygen Consumption Calorimeter, Annual Book of ASTM Standard, 04.07, E 1474-20a, 2017.
  93. Standard Test Method for Determining the Heat Release Rate and Other Fire-Test-Response Characteristics of Wall Covering or Ceiling Covering Composites Using a Cone Calorimeter, Annual Book of ASTM Standard, 04.07, E 1740-20a, 2018.
  94. Standard Test Method for Determination of Fire-Test-Response Characteristics of Components or Composites of Mattresses or Furniture for Use in Correctional Facilities after Exposure to Vandalism, by Employing a Bench Scale Oxygen Consumption Calorimeter, Annual Book of ASTM Standard, 15.08, F 1550-16, 2020.
  95. Standard Test Method for Using a Cone Calorimeter to Determine Fire-Test-Response Characteristics of Insulating Materials Contained in Electrical or Optical Fiber Cables, Annual Book of ASTM Standard, 10.02, D 6113-16, 2020.
  96. Standard Test Method for the Determination of Combustibility Parameters of Building Materials Using an Oxygen Consumption Calorimeter (Cone Calorimeter), ULC-S135, 2018.

 

Iranian Journal of Polymer Science and Technology
Volume 34, Issue 1 - Serial Number 171
May and June 2021
Pages 3-27

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