title: Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6.
abstract: Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy.
authors: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China.
authors: Hua
authors: H
authors: Ge
authors: School of Architecture and Civil Engineering, Anhui University of Technology, 59 Hudong Road, Ma'anshan, Anhui 243002, PR China.
authors: Gang
authors: G
authors: Tang
authors: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China.
authors: Wei-Zhao
authors: WZ
authors: Hu
authors: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China.
authors: Bi-Bo
authors: BB
authors: Wang
authors: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China.
authors: Ying
authors: Y
authors: Pan
authors: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China. Electronic address: leisong@ustc.edu.cn.
authors: Lei
authors: L
authors: Song
authors: State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, PR China; 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: Yuan
authors: Y
authors: Hu
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D002209:Caprolactam / Q000031:analogs & derivatives* / Q000737:chemistry; D005411:Flame Retardants; D006358:Hot Temperature; D008422:Materials Testing; D010720:Phosphines / Q000737:chemistry; D017905:Phosphites / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014227:Triazines / Q000737:chemistry*
chemical_list: D005411:Flame Retardants; D010720:Phosphines; D017905:Phosphites; D011108:Polymers; D014227:Triazines; C009916:nylon 6; C071913:melamine cyanurate; D002209:Caprolactam; D000535:Aluminum; C044646:phosphine
keywords: Aluminum hypophosphite; Flame retardancy; Microencapsulation; Safety