高取向氢氧化镁的改性及其在乙烯-醋酸乙烯酯共聚物中的应用  

Modifications of High-Oriented Magnesium Hydroxide and Its Applications in Ethylene-Vinylacetate Copolymer

作　　者：张金帅 马亚丽 王海棠 司傲龙 郑强 贾松岩 李雪 ZHANG Jinshuai;MA Yali;WANG Haitang;SI Aolong;ZHENG Qiang;JIA Songyan;LI Xue(School of Chemical Engineering,Shenyang University of Chemical Technology,Shenyang 110020,China;Liaoning Magnesium Calcium Inorganic Functional Materials Engineering Research Center,Shenyang 110020,China;Shenyang Key Laboratory of Magnesium and Calcium Resource Utilization Technology,Shenyang 110020,China)

机构地区：[1]沈阳化工大学化学工程学院,辽宁沈阳110020 [2]辽宁省镁钙无机功能材料工程研究中心,辽宁沈阳110020 [3]沈阳市镁钙资源利用技术重点实验室,辽宁沈阳110020

出　　处：《塑料工业》2024年第6期121-129,120,共10页China Plastics Industry

基　　金：科技部重点研发计划课题(2020YFC1909302);辽宁省自然科学基金计划项目(2022-BS-210)。

摘　　要：以菱镁矿煅烧得到的轻烧粉(主要成分为MgO)为原料,硝酸铵溶液为蒸氨母液,改变蒸氨条件提高蒸氨转化率,采用氨循环法合成层状高取向Mg(OH)_(2)。研究了蒸氨过程中硝酸铵的起始物质的量浓度(C_(NH_(4)NO_(3)))、蒸氨温度、氨/镁物质的量比对蒸氨转化率的影响;并以制得的Mg(OH)_(2)为研究对象,采用硅烷偶联剂乙烯基三甲氧基硅烷(HD-171)和乙烯基三(β-甲氧基乙氧基)硅烷(HD-172)作为表面改性剂,对Mg(OH)_(2)进行改性,将改性剂HD-171和HD-172改性后Mg(OH)_(2)添加到乙烯-醋酸乙烯酯共聚物(EVA)中,并对复合材料的拉伸性能和阻燃性进行表征。结果表明,温度、氨/镁物质的量比是影响蒸氨反应镁离子浸出率的关键因素,成功制备出纯度为99.98%、粒径为1.3μm、六方片状的高取向[I(001)/I(101)=1.3,I为晶面衍射峰强度]Mg(OH)_(2)产物。通过对比改性前后Mg(OH)_(2)的吸油值可知:在反应温度75℃,改性剂HD-171的质量分数为4%,反应60 min的条件下,改性剂HD-171对Mg(OH)_(2)的改性效果最好;在反应温度85℃,改性剂HD-172的质量分数为4%,反应60 min的条件下,改性剂HD-172对Mg(OH)_(2)的改性效果最好。在添加剂的质量分数均为70%的情况下,与未改性Mg(OH)_(2)/EVA复合材料相比,HD-171和HD-172改性Mg(OH)_(2)/EVA复合材料的拉伸强度分别提高了4.05和2.53 MPa,氧指数分别提升了2.6%和1.1%,说明HD-171和HD-172改性后的Mg(OH)_(2)可以有效地提高EVA的阻燃性和拉伸性能。The light calcined powder(mainly composed of MgO)obtained from magnesite calcination was used as the raw material,and ammonium nitrate solution was used as the mother liquor for ammonia evaporation.The ammonia evaporation conditions were changed to improve the ammonia conversion rates.Layered highly-oriented Mg(OH)_(2)was synthesized by using the ammonia circulation method.During the ammonia distillation process,the effects of the initial molality of ammonium nitrate(C_(NH_(4)NO_(3))),ammonia temperature,and the ratios of amounts of substance between ammonia and magnesium on the ammonia conversion rates were studied.To modify the prepared Mg(OH)_(2),the silane coupling agents[ethylene trimethoxysilane(HD-171)and ethylene trimethoxysilane(β-Methoxyethoxy silane(HD-172)]were used as the surface modifiers.The HD-171-and HD-172-modified Mg(OH)_(2)additives were added to ethylene-vinylacetate copolymer(EVA).The tensile properties and flame retardancy of the composite materials were characterized.The results show that,temperature and the ratios of amounts of substance between ammonia and magnesium are the key factors affecting the leaching rate of magnesium ions in the ammonia distillation reaction.The Mg(OH)_(2)product with a purity of 99.98%,a particle size of 1.3μm,and a high orientation of hexagonal flakes[I(001)/I(101)=1.3,where I is the diffraction peak intensity of the crystal plane]was successfully prepared.By comparing the oil absorption values of Mg(OH)_(2)before and after modification,the modification effect of modifier HD-171 on Mg(OH)_(2)is the best when the reaction temperature is 75℃,the mass fraction of modifier HD-171 is 4%,and the reaction time is 60 min.The modification effect of modifier HD-172 on Mg(OH)_(2)is the best when the reaction temperature is 85℃,the mass fraction of modifier HD-172 is 4%,and the reaction time is 60 min.When the additive mass fractions of composite materials are 70%,compared with the unmodified Mg(OH)_(2)/EVA composites,the tensile strengths of HD-171-and HD-172-modif

关 键 词：氢氧化镁 高取向 乙烯-醋酸乙烯酯共聚物 硅烷偶联剂 阻燃性 拉伸性能 

分 类 号：TQ323.4[化学工程—合成树脂塑料工业] TQ325.1+2