Self-extinguishing and transparent epoxy resin modified by a phosphine oxide-containing bio-based derivative

Abstract

A phosphine oxide-containing bio-based curing agent was synthesized by addition reaction between furan derivatives and diphenylphosphine oxide. The molecular structure of the as-prepared bio-based curing agent was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Dynamic mechanical analysis results indicated that with the increase of bio-based curing agent content, the glass transition temperature of epoxy/bio-based curing agent composites decreased, which was related to the steric effect of diphenylphosphine oxide species that possibly hinder the curing reaction as well as the reduction in the cross-linking density by mono-functional N-H. By the addition of 7.5 wt-% bio-based curing agent, the resulting epoxy composite achieved UL-94 V-0 rating, in addition to limiting oxygen index of 32.0 vol-%. With the increase of content for the bio-based curing agent, the peak of heat release rate and total heat release of the composites gradually decreased. The bio-based curing agent promoted the carbonization of the epoxy matrix, leading to higher char yield with good thermal resistance. The high-quality char layer served as an effective barrier to retard the diffusion of decomposition volatiles and oxygen between molten polymers and the flame. This study provides a renewable strategy for fabricating flame retardant and transparent epoxy thermoset.

Graphical abstract

Keywords

epoxy resin / flame retardant / furan derivative / diphenylphosphine oxide

References

[1] Guo W W, Nie S, Kalali E N, Wang X, Wang W, Cai W, Song L, Hu Y. Construction of SiO₂@UiO-66 core shell microarchitectures through covalent linkage as flame retardant and smoke suppressant for epoxy resins. Composites. Part B, Engineering, 2019, 176: 107261

[2] Guo W W, Wang X, Gangireddy C S R, Wang J L, Pan Y, Xing W, Song L, Hu Y. Cardanol derived benzoxazine in combination with boron-doped graphene toward simultaneously improved toughening and flame retardant epoxy composites. Composites. Part A, Applied Science and Manufacturing, 2019, 116: 13–23

[3] Wang X, Hu Y, Song L, Xing W Y, Lu H D, Lv P, Jie G X. Flame retardancy and thermal degradation mechanism of epoxy resin composites based on a DOPO substituted organophosphorus oligomer. Polymer, 2010, 51(11): 2435–2445

[4] Kong Q H, Sun Y L, Zhang C J, Guan H M, Zhang J H, Wang D Y, Zhang F. Ultrathin iron phenyl phosphonate nanosheets with appropriate thermal stability for improving fire safety in epoxy. Composites Science and Technology, 2019, 182: 107748

[5] Kong Q H, Wu T, Zhang J H, Wang D Y. Simultaneously improving flame retardancy and dynamic mechanical properties of epoxy resin nanocomposites through layered copper phenylphosphate. Composites Science and Technology, 2018, 154: 136–144

[6] Horold S, Erftstadt D E. Flame-retarding thermosetting compositions. US Patent, 6420459 B1, 2002-07-16

[7] Perret B, Schartel B, Stoss K, Ciesielski M, Diederichs J, Doring M, Kramer J, Altstadt V. Novel DOPO-based flame retardants in high-performance carbon fibre epoxy composites for aviation. European Polymer Journal, 2011, 47(5): 1081–1089

[8] Cai W, Feng X, Wang B, Hu W, Yuan B, Hong N, Hu Y. A novel strategy to simultaneously electrochemically prepare and functionalize graphene with a multifunctional flame retardant. Chemical Engineering Journal, 2017, 316: 514–524

[9] Cai W, Wang J, Pan Y, Guo W, Mu X, Feng X, Yuan B, Wang X, Hu Y. Mussel-inspired functionalization of electrochemically exfoliated graphene: based on self-polymerization of dopamine and its suppression effect on the fire hazards and smoke toxicity of thermoplastic polyurethane. Journal of Hazardous Materials, 2018, 352: 57–69

[10] Cai W, Cai T, He L, Chu F, Mu X, Han L, Hu Y, Wang B, Hu W. Natural antioxidant functionalization for fabricating ambient-stable black phosphorus nanosheets toward enhancing flame retardancy and toxic gases suppression of polyurethane. Journal of Hazardous Materials, 2020, 387: 121971

[11] Cai W, Li Z, Mu X, He L, Zhou X, Guo W, Song L, Hu Y. Barrier function of graphene for suppressing the smoke toxicity of polymer/black phosphorous nanocomposites with mechanism change. Journal of Hazardous Materials, 2021, 404: 124106

[12] Shi Y Q, Liu C, Duan Z P, Yu B, Liu M H, Song P A. Interface engineering of MXene towards super-tough and strong polymer nanocomposites with high ductility and excellent fire safety. Chemical Engineering Journal, 2020, 399: 125829

[13] Shi Y Q, Yu B, Duan L J, Gui Z, Wang B B, Hu Y, Yuen, Rechard K K. Graphitic carbon nitride/phosphorus-rich aluminum phosphinates hybrids as smoke suppressants and flame retardants for polystyrene. Journal of Hazardous Materials, 2017, 332: 87–96

[14] Zhou K Q, Tang G, Gao R, Jiang S D. In situ growth of 0D silica nanospheres on 2D molybdenum disulfide nanosheets: towards reducing fire hazards of epoxy resin. Journal of Hazardous Materials, 2018, 344: 1078–1089

[15] Qiu S L, Zou B, Zhang T, Ren X Y, Yu B, Zhou Y F, Kan Y C, Hu Y. Integrated effect of NH₂-functionalized/triazine based covalent organic framework black phosphorus on reducing fire hazards of epoxy nanocomposites. Chemical Engineering Journal, 2020, 401: 126058

[16] Xu W Z, Yan H Y, Wang G S, Qin Z Q, Fan L J, Yang Y X. A silica-coated metal-organic framework/graphite-carbon nitride hybrid for improved fire safety of epoxy resins. Materials Chemistry and Physics, 2021, 258: 123810

[17] Hergenrother P M, Thompson C M, Smith J G Jr, Connell J W, Hinkley J A, Lyon R E, Moulton R. Flame retardant aircraft epoxy resins containing phosphorus. Polymer, 2005, 46(14): 5012–5024

[18] Mercado L A, Galia M, Reina J A. Silicon-containing flame retardant epoxy resins: synthesis, characterization and properties. Polymer Degradation & Stability, 2006, 91(11): 2588–2594

[19] Hsiue G H, Wang W J, Chang F C. Synthesis, characterization, thermal and flame-retardant properties of silicon-based epoxy resins. Journal of Applied Polymer Science, 1999, 73(7): 1231–1238

[20] Levchik S, Piotrowski A, Weil E, Yao Q. New developments in flame retardancy of epoxy resins. Polymer Degradation & Stability, 2005, 88(1): 57–62

[21] Sponton M, Ronda J C, Galia M, Cadiz V. Flame retardant epoxy resins based on diglycidyl ether of (2,5-dihydroxyphenyl)diphenyl phosphine oxide. Journal of Polymer Science. Part A, Polymer Chemistry, 2007, 45(11): 2142–2151

[22] Zhao J, Dong X, Huang S, Tian X, Song L, Yu Q, Wang Z. Performance comparison of flame retardant epoxy resins modified by DPO-PHE and DOPO-PHE. Polymer Degradation & Stability, 2018, 156: 89–99

[23] Tian X, Yin Q, Wang Z. Synthesis of diphenylphosphine oxide derivative and its flame retardant application in epoxy resin. Journal of Photopolymer Science and Technology, 2020, 32(6): 769–778

[24] Yang D Q, Dong L M, Hou X D, Zheng W K, Xiao J, Xu J Z, Ma H Y. Synthesis of bio-based poly (cyclotriphosphazene-resveratrol) microspheres acting as both flame retardant and reinforcing agent to epoxy resin. Polymers for Advanced Technologies, 2020, 31(1): 135–145

[25] Zhang J H, Mi X Q, Chen S Y, Xu Z J, Zhang D H, Miao M H, Wang J S. A bio-based hyperbranched flame retardant for epoxy resins. Chemical Engineering Journal, 2020, 381: 122719

[26] Ma C, Li J. Synthesis of an organophosphorus flame retardant derived from daidzein and its application in epoxy resin. Composites. Part B, Engineering, 2019, 178: 107471

[27] Xie W Q, Huang S W, Tang D L, Liu S M, Zhao J Q. Biomass-derived Schiff base compound enabled fire-safe epoxy thermoset with excellent mechanical Properties and high glass transition temperature. Chemical Engineering Journal, 2020, 394: 123667

[28] Dai J Y, Teng N, Liu J K, Feng J X, Zhu J, Liu X Q. Synthesis of bio-based fire-resistant epoxy without addition of flame retardant elements. Composites. Part B, Engineering, 2019, 179: 107523

[29] Tian Y Z, Wang Q, Hu Y J, Sun H, Cui Z C, Kou L L, Cheng J, Zhang J Y. Preparation and shape memory properties of rigid-flexible integrated epoxy resins via tunable micro-phase separation structures. Polymer, 2019, 178: 121592

[30] Chi Z Y, Guo Z W, Xu Z C, Zhang M J, Li M, Shang L, Ao Y H. A DOPO-based phosphorus-nitrogen flame retardant bio-based epoxy resin from diphenolic acid: synthesis, flame-retardant behavior and mechanism. Polymer Degradation & Stability, 2020, 176: 109151

[31] Tang G, Wang X, Zhang R, Yang W, Hu Y, Song L, Gong X L. Facile synthesis of lanthanum hypophosphite and its application in glass-fiber reinforced polyamide 6 as a novel flame retardant. Composites. Part A, Applied Science and Manufacturing, 2013, 54: 1–9

[32] Wang X, Song L, Yang H Y, Xing W Y, Kandola B, Hu Y. Simultaneous reduction and surface functionalization of graphene oxide with POSS for reducing fire hazards in epoxy composites. Journal of Materials Chemistry, 2012, 22(41): 22037–22043

[33] Tang G, Liu X L, Zhou L, Zhang P, Deng D, Jiang H H. Steel slag waste combined with melamine pyrophosphate as a flame retardant for rigid polyurethane foams. Advanced Powder Technology, 2020, 31(1): 279–286

[34] Yan Y, Huang P, Zhang H P. Preparation and characterization of novel carbon molecular sieve membrane/PSSF composite by pyrolysis method for toluene adsorption. Frontiers of Chemical Science and Engineering, 2020, 13(4): 772–783

[35] Guo W W, Zhao Y Y, Wang X, Cai W, Wang J L, Song L, Hu Y. Multifunctional epoxy composites with highly flame retardant and effective electromagnetic interference shielding performances. Composites. Part B, Engineering, 2020, 192: 107990

[36] Guo W W, Wang X, Huang J L, Zhou Y F, Cai W, Wang J L, Song L, Hu Y. Construction of durable flame-retardant and robust superhydrophobic coatings on cotton fabrics for water-oil separation application. Chemical Engineering Journal, 2020, 398: 125661

[37] Wang X, Zhou S, Xing W Y, Yu B, Feng X M, Song L, Hu Y. Self-assembly of Ni-Fe layered double hydroxide/graphene hybrids for reducing fire hazard in epoxy composites. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2013, 1(13): 4383–4390

[38] Tang G, Zhou L, Zhang P, Han Z Q, Chen D P, Liu X Y, Zhou Z J. Effect of aluminum diethylphosphinate on flame retardant and thermal properties of rigid polyurethane foam composites. Journal of Thermal Analysis and Calorimetry, 2020, 142(2): 129–137

[39] Zhu Z M, Wang L X, Dong L P. Influence of a novel P/N-containing oligomer on flame retardancy and thermal degradation of intumescent flame-retardant epoxy resin. Polymer Degradation & Stability, 2019, 162: 129–137

RIGHTS & PERMISSIONS

Higher Education Press