title: Flame-retardant-wrapped polyphosphazene nanotubes: A novel strategy for enhancing the flame retardancy and smoke toxicity suppression of epoxy resins.
abstract: The structure of polyphosphazene nanotubes (PZS) is similar to that of carbon nanotubes (CNTs) before modification. For applications of CNTs in polymer composites, surface wrapping is an economically attractive route to achieve functionalized nanotubes. Based on this idea, functionalized polyphosphazene nanotubes (FR@PZS) wrapped with a cross-linked DOPO-based flame retardant (FR) were synthesized via one-step strategy and well characterized. Then, the obtained FR@PZS was introduced into epoxy resin (EP) to investigate flame retardancy and smoke toxicity suppression performance. Thermogravimetric analysis indicated that FR@PZS significantly enhanced the thermal stability of EP composites. Cone calorimeter results revealed that incorporation of FR@PZS obviously improved flame retardant performance of EP, for example, 46.0% decrease in peak heat release rate and 27.1% reduction in total heat release were observed in the case of epoxy composite with 3wt% FR@PZS. The evolution of toxic CO and other volatile products from the EP decomposition was significantly suppressed after the introduction of FR@PZS, Therefore, the smoke toxicity associates with burning EP was reduced. The presence of both PZS and a DOPO-based flame retardant was probably responsible for this substantial diminishment of fire hazard.
authors.affiliation: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China; USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren'ai Road, Suzhou, Jiangsu 215123, PR China.
authors.forename: Shuilai
authors.initials: S
authors.lastname: Qiu
authors.affiliation: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China. Electronic address: wxcmx@ustc.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China; USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren'ai Road, Suzhou, Jiangsu 215123, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China; USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren'ai Road, Suzhou, Jiangsu 215123, PR China.
authors.forename: Xiaming
authors.initials: X
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Mu
authors.affiliation: USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren'ai Road, Suzhou, Jiangsu 215123, PR China; Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
authors.forename: Richard K K
authors.initials: RKK
authors.lastname: Yuen
authors.affiliation: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China; USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren'ai Road, Suzhou, Jiangsu 215123, PR China. Electronic address: yuanhu@ustc.edu.cn.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Hu
keywords: Fire hazard; Flame retardant; Nanocomposites; Polyphosphazene nanotubes; Toxicity suppression