The synthesis of the multifunctional phosphorus-based flame-retardant crosslinking agent is presented here. Gallic acid was selected as a raw material for the production of the desired product because of its availability (bio-based), multifunctional structure, and applicability of the various chemistries. Along with the carboxylic acid group, hydroxyl groups also have the tendency to react with the replaceable halogenated compounds and it was necessary to protect the hydroxyl groups by acetylation. The synthesis procedure follows acetylation, reaction with phenylphosphonic dichloride (PPDC), and deacetylation to obtain the final product (GA-P). The structure confirmation and the progress of the reactions were confirmed using hydroxyl and acid values, Fourier transform infrared (FTIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The formed product was used as a crosslinking agent to produce the polyurethane coatings with different loadings and various thermal, mechanical, and flame-retardant properties that were studied. The thermal and the flame-retardant properties showed significant increase with increasing concentration of GA-P which were studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limiting oxygen index (LOI), and UL-94 tests. The coating with the highest concentration of GA-P showed 27 LOI and self-extinguishing behavior within 10 s of ignition. The mechanical properties deteriorated with increasing concentration of GA-P due to the increased brittleness and crosslinking density.
This is a preview of subscription content, log in to check access.
Buy single article
Instant unlimited access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Pajerski, A, Ahrens, G, “1K Polyurethane for Conventional 2K Applications.” Paint Coat. Ind., 25 (2) 34–40 (2009)
Melchiors, M, Sonntag, M, Kobusch, C, Jürgens, E, “Recent Developments in Aqueous Two-Component Polyurethane (2K-PUR) Coatings.” Prog. Org. Coat., 40 99–109 (2000). https://doi.org/10.1016/S0300-9440(00)00123-5
Fiori, DE, “Two-Component Water Reducible Polyurethane Coatings.” Prog. Org. Coat., 32 65–71 (1997). https://doi.org/10.1016/S0300-9440(97)00076-3
Sonntag, M, “Aqueous Two-Pack Polyurethane (2K-PUR) Coatings for Automotive Refinish and Commercial Vehicles Focus.” Surf. Coat. Int., 82 456–457 (1999). https://doi.org/10.1007/BF02692650
Michael, JD, “Using High Performance Two-Component Waterborne Polyurethane Wood Coatings.” J. Coat. Technol., 69 1–2 (1997). https://doi.org/10.1007/bf02696145
Zand, BN, Mahdavian, M, “Corrosion and Adhesion Study of Polyurethane Coating on Silane Pretreated Aluminum.” Surf. Coat. Technol., 203 1677–1681 (2009). https://doi.org/10.1016/j.surfcoat.2008.12.027
Agger, RT, “Survey of Polyurethane Adhesives.” Int. J. Adhes. Adhes., 4 151–152 (1984). https://doi.org/10.1016/0143-7496(84)90022-8
Wu, G, Kong, Z, Chen, C, Chen, J, “Crosslinking Reaction and Properties of Two-Component Waterborne Polyurethane from Terpene-Maleic Ester Type Epoxy Resin.” J. Appl. Polym. Sci., 128 132–138 (2013). https://doi.org/10.1002/app.38130
Babu Raghu, Ch, Sowjany, N, Sarvamangala, D, “Production of Gallic Acid—A Short Review.” IJSRM, 4 125–132 (2016)
Shi, X, Jiang, S, “Establishment of a Highly Efficient Flame-Retardant System for Rigid Polyurethane Foams Based on Bi-Phase Flame-Retardant Actions.” RSC Adv., 8 9985–9995 (2018). https://doi.org/10.1039/c7ra13315d
Levchik, SV, Weil, ED, “A Review of Recent Progress in Phosphorus-Based Flame Retardants.” J. Fire Sci., 24 345–362 (2006). https://doi.org/10.1177/0734904106068426
Wazarkar, K, Kathalewar, M, Sabnis, A, “Improvement in Flame Retardancy of Polyurethane Dispersions by Newer Reactive Flame Retardant.” Prog. Org. Coat., 87 75–82 (2015). https://doi.org/10.1016/j.porgcoat.2015.05.016
Zhang, P, Tian, S, Fan, H, Chen, Y, Yan, J, “Flame Retardancy and Hydrolysis Resistance of Waterborne Polyurethane Bearing Organophosphate Moieties Lateral Chain.” Prog. Org. Coat., 89 170–180 (2015). https://doi.org/10.1016/j.porgcoat.2015.09.015
Xu, D, Yu, K, Qian, K, “Effect of Tris(1-chloro-2-propyl) Phosphate and Modified Aramid Fiber on Cellular Structure, Thermal Stability and Flammability of Rigid Polyurethane Foams.” Polym. Degrad. Stab., 144 207–220 (2017). https://doi.org/10.1016/j.polymdegradstab.2017.08.019
Chen, M, Shao, Z, Wang, X, Chen, L, Wang, Y, “Halogen-Free Flame-Retardant Flexible Polyurethane Foam with a Novel Nitrogen–Phosphorus Flame Retardant.” Ind. Eng. Chem. Res., 51 9769–9776 (2012). https://doi.org/10.1021/ie301004d
Rao, WH, Xu, HX, Xu, YJ, Qi, M, Liao, W, Xu, S, Wang, WZ, “Persistently Flame-Retardant Flexible Polyurethane Foams by a Novel Phosphorus-Containing Polyol.” Chem. Eng. J., 343 198–206 (2018). https://doi.org/10.1016/j.cej.2018.03.013
Sonnier, R, Taguet, A, Ferry, L, Lopez-Cuesta, JM, Towards Biobased Flame Retardant Polymers (2018). https://doi.org/10.1007/978-3-319-67083-6
Howell, BA, Oberdorfer, KL, Ostrander, EA, “Phosphorus Flame Retardants for Polymeric Materials from Gallic Acid and Other Naturally Occurring Multihydroxybenzoic Acids.” Int. J. Polym. Sci., 18 12 (2018). https://doi.org/10.1155/2018/7237236
Mestry, S, Kakatkar, R, Mhaske, ST, “Cardanol Derived P and Si Based Precursors to Develop Flame Retardant PU Coating.” Prog. Org. Coat., 129 59–68 (2019). https://doi.org/10.1016/j.porgcoat.2018.12.016
Gu, JW, Zhang, GC, Dong, SL, Zhang, QY, Kong, J, “Study on Preparation and Fire-Retardant Mechanism Analysis of Intumescent Flame-Retardant Coatings.” Surf. Coat. Technol., 201 7835–7841 (2007). https://doi.org/10.1016/j.surfcoat.2007.03.020
Ding, H, Xia, C, Wang, J, Wang, C, “Inherently Flame-Retardant Flexible Bio-Based Polyurethane Sealant with Phosphorus and Nitrogen-Containing Polyurethane Prepolymer.” Polym. Degrad. Stab., 51 5008–5018 (2016). https://doi.org/10.1007/s10853-016-9805-y
Mestry, S, Mhaske, ST, “Synthesis of Epoxy Resins Using Phosphorus-Based Precursors for Flame-Retardant Coating.” J. Coat. Technol. Res., 16 (3) 807–818 (2019). https://doi.org/10.1007/s11998-018-00157-3
Mulge, S, Mestry, S, Naik, D, Mhaske, S, “Phosphorus-Containing Reactive Agent for UV-Curable Flame-Retardant Wood Coating.” J. Coat. Technol. Res., 16 (5) 1493–1502 (2019). https://doi.org/10.1007/s11998-019-00224-3
Patel, M, Mestry, S, Phalak, G, Mhaske, S, “Novel Catechol-Derived Phosphorus-Based Precursors for Coating Applications.” Polym. Bull., 1–21 (2019). https://doi.org/10.1007/s00289-019-02855-3
Guo, Y, Lyu, Z, Yang, X, Lu, Y, Ruan, K, Wu, Y, Kong, J, Gu, J, “Enhanced Thermal Conductivities and Decreased Thermal Resistances of Functionalized Boron Nitride/Polyimide Composites.” Composites Part B (2019). https://doi.org/10.1016/j.compositesb.2019.01.099
Gu, J, Lv, Z, Wub, Y, Guo, Y, Tian, L, Qiu, H, Li, W, Zhang, Q, “Dielectric Thermally Conductive Boron Nitride/Polyimide Composites with Outstanding Thermal Stabilities via In Situ Polymerizationelectrospinning-Hot Press Method.” Composites: Part A, 94 209–216 (2017). https://doi.org/10.1016/j.compositesa.2016.12.014
Tang, L, Dang, J, He, M, Li, J, Kong, J, Tang, Y, Gu, J, “Preparation and Properties of Cyanate-Based Wave-Transparent Laminated Composites Reinforced by Dopamine/POSS Functionalized Kevlar Cloth.” Compos. Sci. Technol., 169 120–126 (2019). https://doi.org/10.1016/j.compscitech.2018.11.018
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Patel, M., Mestry, S., Khuntia, S.P. et al. Gallic acid-derived phosphorus-based flame-retardant multifunctional crosslinking agent for PU coating. J Coat Technol Res 17, 293–303 (2020). https://doi.org/10.1007/s11998-019-00273-8
- Gallic acid