Synthesis of the Zinc Borate Modified Expanded Graphite and Its Influence on Polyurethane Foam Properties

International Journal of Applied Chemistry

© 2019 by SSRG - IJAC Journal

Volume 6 Issue 2

Year of Publication : 2019

Authors : Gang Bian ,Jianing Liu , Xiuyan Pang

10.14445/23939133/IJAC-V6I2P106

How to Cite?

Gang Bian ,Jianing Liu , Xiuyan Pang, "Synthesis of the Zinc Borate Modified Expanded Graphite and Its Influence on Polyurethane Foam Properties," SSRG International Journal of Applied Chemistry, vol. 6,  no. 2, pp. 35-40, 2019. Crossref, https://doi.org/10.14445/23939133/IJAC-V6I2P106

Abstract:

In order to get the graphite intercalation compound with low sulfur content, high expansibility and fire resistance, the synthetic method of expandable graphite modified by zinc borate (EGZn) was investigated, and its influence on rigid polyurethane foam (RPUF) structure, compress strength and flame retardancy was also carried out. The feasible preparing condition of EGZn was determined to be: mass ratio of graphite C, KMnO4, H2SO4 (98 wt%) and 2ZnO·3B2O3·3.5H2O was 1.0:0.25:4.5:0.3, the used H2SO4 should be diluted to 75 wt% before reaction, and the reaction lasts 40min at 50℃. Expansion properties, X-ray powder diffractiometer and Fourier transform infrared spectroscopy testified the existence of EGZn. Addition of EGZn is not conducive to the formation of the cell structure, which causes an increase in foam density and a decrease in compressive strength. However, addition of EGZn at a 30 wt% can increase the limiting oxygen index of RPUF to 26.9%, and increased by 31.2%. The vertical burning level increases to V-0. The flame retardation is come from form protection of “worm-like” expanded graphite residues. At the same time, the expansion process absorbs a large amount of heat and release CO2, H2O and SO2 gases.

Keywords:

expandable graphite, zinc borate, flame retardancy, rigid polyurethane foam, structure and property

References:

[1] Saba, N.; Jawaid, M.; Alothman, O. Y.; Inuwa, I. M.; Hassan, A. A review on potential development of flame retardant kenaf fibers reinforced polymer composites. Polym. Advan. Technol. 2017, 28, 424.
[2] Wang, K.; Morgan, A. B.; Benin, V. Preparation and studies of new phosphorus-containing diols as potential flame retardants. Fire Mater. 2017, 41, 973.
[3] Kruger, H. J; Focke, W. W.; Mhike, W; Taute, A; Roberson, A. Thermal properties of polyethylene flame retarded with expandable graphite and intumescent fire retardant additives. Fire Mater. 2017, 41, 573.
[4] Ming, G.; Chen, S.; Sun, Y. J.; Wang, Y. X. Flame retardancy and thermal properties of flexible polyurethane foam containing expanded graphite. Combust. Sci. Technol. 2017, 189, 793.
[5] Xie, R.; Qu, B. Expandable graphite systems for halogen-free flame-retarding of polyolefins. I. Flammability characterization and synergistic effect. J. Appl. Polym. Sci. 2010, 80, 1881.
[6] Wang, B. B.; Hu, S.; Zhao, K. M.; Lu, H. D.; Song, L.; Hu, Y. Preparation of polyurethane microencapsulated expandable graphite, and its application in ethylene vinyl acetate copolymer containing silica-gel microencapsulated ammonium polyphosphate. Ind. Eng. Chem. Res. 2011, 50, 11476.
[7] Chen, X. L.; Zhuo, J. L.; Song, W. K.; Jiao, C. M.; Qian, Y.; Li, S. X. Flame retardant effects of organic inorganic hybrid intumescent flame retardant based on expandable graphite in silicone rubber composites. Polym. Advan. Technol. 2014, 25, 1530.
[8] Hong, S. G.; Chang, S. Y. Fire performance and mechanical properties of acrylonitrile-butadiene-styrene copolymer/modified expandable graphite composites. Fire Mater. 2012, 36, 277.
[9] Kabakci, E.; Sayer, G.; Suvaci, E.; Uysal, O.; Güler, İ.; Kaya, M. Processing-structure-property relationship in rigid polyurethane foams. J. Appl. Polym. Sci. 2017, 134, 44870.
[10] Azahari, M. S. M; Rus, A. Z. M.; Zaliran, M. T.; Kormin, S. Improving sound absorption property of polyurethane foams doped with natural fiber. IOP Conference Series: Mat. Sci. Eng. 2017, 226, 012009.
[11] Modesti, M.; Lorenzetti, A.; Simioni, F.; Camino, G. Expandable graphite as an intumescent flame retardant in polyisocyanurate polyurethane foams. Polym. Degrad. Stab. 2002, 77, 195.
[12] Liu, L.; Wang, X.; Wang, G.; Xu, B.; Xu, W. Synergistic effect of expandable graphite and α‐type zirconium phosphate on flame retardancy of polyurethane elastomer. J. Appl. Polym. Sci. 2017, 134, 45188.
[13] Sorokina, N. E.; Khaskov, M. A.; Avdeev, V. V.; Nikol’Skaya, I. V. Reaction of graphite with sulfuric acid in the presence of KMnO4. Russ. J. Gen. Chem. 2005, 75, 162.
[14] Chung, D. D. L. A review of exfoliated graphite. J. Mater. Sci. 2016, 51, 554.
[15] Pang, X. Y.; Tian, Y.; Weng, M. Q. Preparation of expandable graphite with silicate assistant intercalation and its effect on flame retardancy of ethylene vinyl acetate composites. Polym. Composite. 2015, 36, 1407.
[16] Huang, J. D.; Tang, Q. Q.; Liao, W. B.; Wang, G. C.; Wei, W.; Li, C. Z. Green preparation of expandable graphite and its
application in flame-resistance polymer elastomer. Ind. Eng. Chem. Res. 2017, 56, 5253.
[17] Xue, E. Y.; Zeng, M. X. Flame retardant science and application. Beijing: National defense industrial press. 1988, 100.
[18] Li, S. L.; Long, B. H.; Wang, Z. C.; Tian, Y. M.; Zheng, Y. H.; Zhang, Q. Synthesis of hydrophobic zinc borate nanoflakes and its effect on flame retardant properties of polyethylene. J. Solid State Chem. 2010, 183, 957.
[19] Pang, X. Y.; Chang, W. S.; Chang, R.; Weng, M. Q. Influence of titanum dioxide modified expandable graphite and ammonium polyphosphate on combustion behavior and physicomechanical property of rigid polyurethane foam. Inte. Polym. Proc. 2018, 33, 117.
[20] Zhao, H.; Zhou, W.; Cao, N. Z.; Shen, W.C.; Zheng, Y. P. Pore structure of exfoliated graphite and its varieties of liquid sorption. Chinese Mater. Sci. Eng. 2002, 20, 153.
[21] Redondo-Foj, B.; Ortiz-Serna, P.; Carsí, M.; Sanchis, M. J.; Culebras, M.; Gómez, C.M.; Cantarero, A. Electrical conductivity properities of expanded graphite-polycarbonnatediol polyurethane composites. Polym. Inter. 2015, 64, 284.
[22] Ebert, L. B. Intercalation compounds of graphite. Annual. Rev. Mater. Sci. 1976, 6, 181.
[23] Xia, S. P.; Gao, S. Y.; Li, J.; Li, W. IR spectra of borate. J. Salt Lake Sci. (Chinese), 1995, 3, 49.
[24] Thirumal, M.; Khastgir, D.; Nando, G. B.; Naik, Y. P; Singha, N. K. Halogen-free flame retardant PUF: Effect of melamine compounds on mechanical, thermal and flame retardant properties. Polym. Degrad. Stab. 2010, 95, 1138.
[25] Pang, X. Y.; Chang, R.; Weng, M. Q. Halogen-free flame retarded rigid polyurethane foam: the influence of titanium dioxide modified expandable graphite and ammonium polyphosphate on flame retardancy and thermal stability. Polym. Eng. Sci. 2018, 58, 2008.
[26] Duquesne, S.; Bras, M. L.; Bourbigot, S.; Delobel, R.; Camino, G.; Eling, B.; Lindsay, C.; Roels, T.; Vezin, H. Mechanism of fire retardancy of polyurethanes using ammonium polyphosphate. J. Appl. Polym. Sci. 2001, 82, 3262.