Atomistic simulation of defected magnesium hydroxide as flame retardants  

阻燃用含缺陷氢氧化镁的原子尺度模拟(英文)

作　　者：张冬云[1,2,3] 杨萍[1] 都政 袁秋华[1] 宋申华[3] 任祥忠[1] 张培新[1] 

机构地区：[1]深圳大学化学与环境工程学院,深圳518060 [2]国家超级计算深圳中心,深圳518055 [3]哈尔滨工业大学深圳研究生院材料科学与工程学院,深圳518055

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第12期4080-4088,共9页中国有色金属学报（英文版）

基　　金：Projects(51174138;20971088)supported by the National Natural Science Foundation of China;Project(JCYJ20130329102720840)supported by Shenzhen Government’s Plan of Science and Technology;China

摘　　要：The mechanical properties and the point defect energy of magnesium hydroxide（Mg（OH）2） were studied using the molecular dynamics. Moreover, the microelectronic structure of Mg（OH）2 with point defects in the bulk and on its surface were investigated using the first principles. The simulation results indicate that Mg（OH）2 was easily modified by other cations because of its strong, favorable interstitial and substitution defects via point defect energy calculation. Mg（OH）2 can provide high-efficiency flame retardancy because of the strong OH（OH Schottky defect） or H bond（H Frenkel defect and Schottky defect）. The potential model of Mg（OH）2 was established, and molecular dynamics simulation was used to investigate the relations between the crystal structure and the mechanical properties. Mg（OH）2 with special morphology such as nano-sheets was a prior consideration to maintain the composite mechanical properties. The detailed electronic structures of Mg（OH）2 with defects were determined. This work may provide theoretical guidance for choosing dopant element and reveal the element doping mechanism of Mg（OH）2.采用分子动力学方法研究氢氧化镁的力学性能和点缺陷能,而对体相和表面所含点缺陷的微观电子结构采用第一性原理进行研究。结果表明,根据缺陷能分析,阳离子间隙和置换缺陷非常容易产生,因此对于氢氧化镁通过引入其他阳离子进行改性相对容易。高的OH键(OH Schottky缺陷)或H键(H的Frenkel缺陷和Schottky缺陷)提高了氢氧化镁脱水过程所获得熵的能垒,从而提高了氢氧化镁的分解温度,这是氢氧化镁能够满足填充型阻燃添加剂的要求本质原因之一。建立了氢氧化镁MD模拟的势能模型,通过模拟计算揭示了氢氧化镁晶体结构与力学性能的关系。为了获得具有较好机械加工性能的添加型阻燃剂,应选薄层状氢氧化镁。确定了含点缺陷氢氧化镁的电子结构。揭示了离子掺杂对氢氧化镁晶体的影响机制,为掺杂离子的选择提供了理论指导。

关 键 词：Mg（OH）2 density functional theory molecular dynamics DEFECTS electronic structure 

分 类 号：TQ132.2[化学工程—无机化工]