Organically modified montmorillonite as a synergist for intumescent flame retardant against the flammable polypropylene |
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Authors: | Panyue Wen Dong Wang JiaJia Liu Jing Zhan Yuan Hu Richard K K Yuen |
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Institution: | 1. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, P.R. China;2. Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute of University of Science and Technology of China, Jiangsu, P.R. China;3. School of Civil Engineering and Environmental Engineering, Anhui Xinhua University, Hefei, Anhui, P.R. China;4. Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong |
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Abstract: | Low flame retardant efficiency is a key bottleneck for currently available retardants against the flammable polypropylene (PP). Herein, the organically modified montmorillonite (OMMT) was utilized as a synergist for our previously reported intumescent flame retardant (IFR) that was constructed from ammonium polyphosphate (APP) and hyperbranched charring foaming agent (HCFA) to further enhance the retardant efficiency against PP. The resultant's combustion behavior was thoroughly investigated by cone calorimetry, limiting oxygen index (LOI), vertical burning test (UL‐94), and scanning electron microscopy (SEM). The results showed that 20% addition of IFR with OMMT showed a positive effect and improved the flame retardancy of the PP systems. Especially, addition of 2 wt% OMMT obviously increased the LOI values of PP systems with 20% total loading flame retardants from 29% to 31.5% and the samples meet V‐0 rating as well as the reduction of the heat release rate (HRR), total heat release (THR), CO2, and CO production occurred. On the other hand, the SEM images were also revealed that OMMT initiated a dense and strong char on the surface of the material, which resulted in efficient flame retardancy of PP matrix during combustion. In addition, thermal degradation behavior discussed by thermogravimetric analysis (TGA) indicated that OMMT could improve the thermal stability of PP systems under high temperature, and promoted char residues of PP/IFR systems. Copyright © 2016 John Wiley & Sons, Ltd. |
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Keywords: | montmorillonite polypropylene hyperbranched charring foaming agent flame retardant |
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