A new microcrystal muscovite composite superabsorbent was synthesized by UV photopolymerization using 2-hydroxy-2-methylpropiophenone（1 173） as photoinitiator,N,N-methylene bisacrylamide（MBA） as crosslinker,acryli...A new microcrystal muscovite composite superabsorbent was synthesized by UV photopolymerization using 2-hydroxy-2-methylpropiophenone（1 173） as photoinitiator,N,N-methylene bisacrylamide（MBA） as crosslinker,acrylic acid（AA）,acrylamide（AM） and sodium 4-styrenesulfonate（SSS） as comonomers.Factors affecting water and salt absorption of the microcrystal muscovite composite superabsorbent,such as crosslinker amount,microcrystal muscovite concentration,photoinitiator content,and SSS concentration,were systematically studied.Water retention capacity of the composite superabsorbent was also investigated.The results show that microcrystal muscovite composite superabsorbent has water absorbency of 550 g/g,salt absorbency of 62 g/g,and water retention of 60% after heating at 70 ℃ for 40 h.The microcrystal muscovite is physically combined into the polymeric network without destroying its polycrystalline structure and the surface of the microcrystal muscovite composite superabsorbent has some deep and small holes.展开更多
High spinning speed 1H magic-angle spinning nuclear magnetic resonance (1H MAS NMR) was used to detect surface hydroxyl groups of diatomite, which include isolated hydroxyl groups and hydrogen-bonded hydroxyl groups, ...High spinning speed 1H magic-angle spinning nuclear magnetic resonance (1H MAS NMR) was used to detect surface hydroxyl groups of diatomite, which include isolated hydroxyl groups and hydrogen-bonded hydroxyl groups, and water adsorbed on diatomite surface that include pore water and hydrogen-bonded water. The corresponding proton chemical shifts of above species are ca. 2.0, 6.0-7.1, 4.9 and 3.0 respectively. Accompanied by thermal treatment temperature ascending, the pore water and hydrogen-bonded water are desorbed successively. As a result, the relative intensities of the peaks assigned to protons of isolated hydroxyl groups and hydrogen-bonded hydroxyl groups increase gradually and reach their maxima at 1000℃. After 1100℃ calcination, the hydroxyl groups that classified to strongly hydrogen-bonded ones and the isolated hydroxyl groups condense basically. But some weakly hydrogen-bonded hydroxyl groups may still persist in the micro-pores.展开更多
基金Funded by Sichuan Provincial Science&Technology Pillar Program,China(Nos.2010GZ0128,2014GZX0010)Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,China(No.SKLGP2012K004)the Sichuan Youth Science and Technology Innovation Research Team Funding Scheme,China(No.2013TD0005)
文摘A new microcrystal muscovite composite superabsorbent was synthesized by UV photopolymerization using 2-hydroxy-2-methylpropiophenone（1 173） as photoinitiator,N,N-methylene bisacrylamide（MBA） as crosslinker,acrylic acid（AA）,acrylamide（AM） and sodium 4-styrenesulfonate（SSS） as comonomers.Factors affecting water and salt absorption of the microcrystal muscovite composite superabsorbent,such as crosslinker amount,microcrystal muscovite concentration,photoinitiator content,and SSS concentration,were systematically studied.Water retention capacity of the composite superabsorbent was also investigated.The results show that microcrystal muscovite composite superabsorbent has water absorbency of 550 g/g,salt absorbency of 62 g/g,and water retention of 60% after heating at 70 ℃ for 40 h.The microcrystal muscovite is physically combined into the polymeric network without destroying its polycrystalline structure and the surface of the microcrystal muscovite composite superabsorbent has some deep and small holes.
基金This work was supported by the Guangdong Provincial Natural Science Foundation (Grant No. 980748) the Foundation of the State Key Laboratory for Physical Chemistry of Solid Surfaces in Xiamen University (Grant No. 9911) and the President Foundation o
文摘High spinning speed 1H magic-angle spinning nuclear magnetic resonance (1H MAS NMR) was used to detect surface hydroxyl groups of diatomite, which include isolated hydroxyl groups and hydrogen-bonded hydroxyl groups, and water adsorbed on diatomite surface that include pore water and hydrogen-bonded water. The corresponding proton chemical shifts of above species are ca. 2.0, 6.0-7.1, 4.9 and 3.0 respectively. Accompanied by thermal treatment temperature ascending, the pore water and hydrogen-bonded water are desorbed successively. As a result, the relative intensities of the peaks assigned to protons of isolated hydroxyl groups and hydrogen-bonded hydroxyl groups increase gradually and reach their maxima at 1000℃. After 1100℃ calcination, the hydroxyl groups that classified to strongly hydrogen-bonded ones and the isolated hydroxyl groups condense basically. But some weakly hydrogen-bonded hydroxyl groups may still persist in the micro-pores.
