title: The reactivity of nano silica with calcium hydroxide.
abstract: The reactivity of nano silica (SiO₂) with calcium hydroxide (Ca(OH)₂) was evaluated and characterized in this study. Ca(OH)₂ activated nano SiO₂ takes place through an exothermic process, which is mainly attributed to the breakdown of Si-O-Si bonds. Ca(2+) offsets the charge imbalance and bonds to Si-OH and Si-O(-) giving rise to calcium silicate hydrate (CSH) gel. Care has to be taken that the reactivity of nano SiO₂ with Ca(OH) ₂significantly depends on the Q³ percentage in nano SiO ₂. Q³ percentages significantly influence the reaction kinetic of nano SiO₂ . The higher Q³ percentage results in a higher reaction degree of nano SiO₂ with Ca(OH)₂ and shorter setting times of the pastes. The higher Q³ percentage results in a lower total reaction heat of nano SiO₂ with Ca(OH)₂. It is suggested that the Q³ percentages of nano SiO₂ should be in excess of 30% to keep the satisfactory setting properties of the pastes for the application requirements of bone cement.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lin
authors.forename: Zhongzi
authors.initials: Z
authors.lastname: Xu
authors.forename: Xianghui
authors.initials: X
authors.lastname: Lan
authors.forename: Yaru
authors.initials: Y
authors.lastname: Ni
authors.forename: Chunhua
authors.initials: C
authors.lastname: Lu
mesh_terms: D001843:Bone Cements / Q000737:chemistry; D002126:Calcium Hydroxide / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning / Q000379:methods; D006358:Hot Temperature; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D011208:Powders; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D001843:Bone Cements; D011208:Powders; D012822:Silicon Dioxide; D002126:Calcium Hydroxide; D010100:Oxygen