Preparation of halogen-free flame retardant polyacrylonitrile via hydrolyzing and grafting with diphenylphosphinyl chloride |
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Authors: | Xiangfu Zhou Lifeng Bai Ziping Song Xuan Yang |
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Institution: | 1. School of Materials Science and Engineering, Tianjin Polytechnic University, 300387, Tianjin, China;2. liuxiaohui@tjpu.edu.cn;4. Analytical and Testing center, Tianjin Polytechnic University, Tianjin, 300387, China |
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Abstract: | AbstractHalogen-free flame retardant polyacrylonitrile (PAN) was prepared via hydrolyzing the nitrile groups of PAN using aqueous sodium carbonate solution/hydrogen peroxide followed by grafting with diphenylphosphinyl chloride. The structure of original PAN, hydrolyzed PAN (HPAN), and flame retardant PAN (FR-PAN) samples were characterized using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and 1H NMR spectroscopy. The thermal properties of the materials were assessed using thermogravimetric analysis. The FTIR spectroscopy indicates that a carbonyl group is present in hydrolyzed HPAN and some characteristic PAN absorption peaks decreased slightly upon hydrolysis. The XPS results show that FR-PAN contained phosphorus, indicating that diphenylphosphinyl chloride has been grafted onto HPAN, which is in accordance with the phenomenon of the self-extinguishing phenomena of FR-PAN during burning experiments. The TG curves indicate the presence of a char residue for FR-PAN of 45% at 800?°C, a higher char residue than that of original PAN (39%). Therefore, FR-PAN displays better thermal stability and char forming capability than does the untreated polymer. |
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Keywords: | Polyacrylonitrile hydrolyzing grafting flame retardant thermal stability |
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