Dual Fire Retardant Action: The Combined Gas and Condensed Phase Effects of Azo-Modified NiZnAl Layered Double Hydroxide on Intumescent Polypropylene

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• 作者：Peng-Ji Wang ; Xiao-Ping HuDui-Jun Liao ; Yi Wen ; T. Richard Hull ; Fei Miao ; Quan-Tong Zhang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：February 1, 2017
• 年：2017
• 卷：56
• 期：4
• 页码：920-932
• 全文大小：1011K
• ISSN：1520-5045

文摘

A ternary nickel-substituted layered double hydroxide, ZnNiAl-CO₃ LDH (C-LDH), was synthesized. It was intercalated with azobenzene-4,4′-dicarboxylic acid using an ion exchange method to obtain organically modified NiZnAl LDH (O-LDH). Both LDHs were melt-blended into polypropylene (PP) with an intumescent fire retardant (IFR). The structure, morphology, thermal stability, and combustible properties of intercalated LDH and its hybrid composite have been comprehensively characterized. Scanning electron microscopy and energy-dispersive X-ray mapping showed that O-LDH exhibits better dispersion than C-LDH. Cone calorimetry showed that the addition of IFR and LDH significantly reduces the smoke and heat release rates. The composite with 1 wt % O-LDH, which showed dual gas-phase and condensed-phase fire retardant action, exhibited the lowest flammability with an limiting oxygen index value of 29.3% and achieved a UL-94 V-0 rating. In addition, incorporation of LDH improved the mechanical properties compared with PP/IFR composites. UV absorption showed that O-LDH could significantly improve the UV stability of PP composites.