title: Ultrathin Nanosheets of Organic-Modified β-Ni(OH)2 with Excellent Thermal Stability: Fabrication and Its Reinforcement Application in Polymers.
abstract: β-Nickel hydroxide (β-Ni(OH)2), which combines two-dimensional (2D) structure and the catalytic property of nickel-containing compounds, has shown great potential for the application in polymer nanocomposites. However, conventional β-Ni(OH)2 exhibits large thickness, poor thermal stability, and irreversible aggregation in polymer matrices, which limits its application. Here, we use a novel phosphorus-containing organosilane to modify the β-Ni(OH)2 nanosheet, obtaining a new β-Ni(OH)2 ultrathin nanosheet with excellent thermal stability. When compared to pristine β-Ni(OH)2, the organic-modified β-Ni(OH)2 (M-Ni(OH)2) maintains nanosheet-like structure, and also presents a small thickness of around 4.6 nm and an increased maximum degradation temperature by 41 °C. Owing to surface organic-modification, the interfacial property of M-Ni(OH)2 nanosheets is enhanced, which results in the exfoliation and good distribution of the nanosheets in a PMMA matrix. The addition of M-Ni(OH)2 significantly improves the mechanical performance, thermal stability, and flame retardancy of PMMA/M-Ni(OH)2 nanocomposites, including increased storage modulus by 38.6%, onset thermal degradation temperature by 42 °C, half thermal degradation temperature by 65 °C, and decreased peak heat release rate (PHRR) by 25.3%. Moreover, it is found that M-Ni(OH)2 alone can catalyze the formation of carbon nanotubes (CNTs) during the PMMA/M-Ni(OH)2 nanocomposite combustion, which is a very helpful factor for the flame retardancy enhancement and has not been reported before. This work not only provides a new 2D ultrathin nanomaterial with good thermal stability for polymer nanocomposites, but also will trigger more scientific interest in the development and application of new types of 2D ultrathin nanomaterials.
authors.affiliation: †School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road 381, Guangzhou 510641, P. R. China.
authors.forename: Saihua
authors.initials: S
authors.lastname: Jiang
authors.affiliation: ‡State Key Laboratory of Fire Science, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230027, P. R. China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Gui
authors.affiliation: †School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road 381, Guangzhou 510641, P. R. China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Chen
authors.affiliation: §Key Lab of Fire Science and Technology of Guangdong Province, Sun Yat-sen University, Guangzhou, Guangdong 510006, P. R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Liang
authors.affiliation: †School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road 381, Guangzhou 510641, P. R. China.
authors.forename: Jahangir
authors.initials: J
authors.lastname: Alam
keywords: catalytic effect; flame retardancy; interface property; mechanical performance; organically modification; polymer nanocomposites; thermal stability; β-Ni(OH)2 ultrathin nanosheets