【作者】 陈旭；

【导师】 韩跃新； 印万忠；

【作者基本信息】 东北大学 ， 矿物粉体材料与工程， 2008， 硕士

【摘要】 碱式硫酸镁晶须和氢氧化镁晶须是无机增韧阻燃材料,可用于塑料、陶瓷、涂料、金属、化工、航空航天等领域,在世界范围内得到越来越广泛的应用。然而在我国此类产品却仍然处于研究与开发阶段,与美日等发达国家相比有较大差距。针对这种情况,本文在前人研究的基础上,系统的研究了碱式硫酸镁晶须和氢氧化镁晶须的制备、改性及应用。以菱镁矿为原料,在700℃下煅烧3h,将煅烧后的活性氧化镁配制为4.0%的料浆,利用水热法,控制反应温度为200℃,反应时间4h,搅拌速度为400r/min,制备出碱式硫酸镁晶须。以氢氧化钠和碱式硫酸镁晶须为原料,采用水热法,控制碱式硫酸镁晶须的料浆浓度为4.0%,反应温度为180℃,反应时间4h,搅拌速度为100r/min,氢氧化钠与碱式硫酸镁晶须的摩尔比为1.4:1时,制备出氢氧化镁晶须。采用单因素条件试验方法,利用脂肪酸、钛酸酯、硅烷、铝酸酯等表面改性剂对碱式硫酸镁晶须和氢氧化镁晶须进行湿法表面改性。试验结果表明,对碱式硫酸镁晶须和氢氧化镁晶须改性效果较好的改性剂分别为硬脂酸钠和硬脂酸锌。改性后碱式硫酸镁晶须和氢氧化镁晶须的接触角、活化指数和吸油量分别能达到111.85°、99.28%、186ml/100g和126.38°、99.05%、354ml/100g,晶须的分散性和流动性也明显提高,晶须表面与硬脂酸盐之间除有物理吸附外,还形成了牢固的化学吸附。将改性后的碱式硫酸镁晶须和氢氧化镁晶须添加到聚丙烯树脂中,随着晶须添加量的增加,碱式硫酸镁晶须/聚丙烯复合材料和氢氧化镁晶须/聚丙烯复合材料的冲击强度和氧指数上升,拉伸强度和断裂伸长率下降。聚丙烯的冲击强度、拉伸强度、断裂伸长率和氧指数分别为62J/m、25.8MPa、83.5％和19.2%,当晶须的添加量为50%时,碱式硫酸镁晶须/聚丙烯复合材料的冲击强度、拉伸强度、断裂伸长率和氧指数分别为79.67J/m、20.6 MPa、9.7％和25.1%,氢氧化镁晶须/聚丙烯复合材料的冲击强度、拉伸强度、断裂伸长率和氧指数分别为75J/m、21MPa、7.2％、26.0％,复合材料的综合力学性能和阻燃性能得到提高。研究了碱式硫酸镁晶须和氢氧化镁晶须增韧阻燃聚丙烯的作用机理,结果表明,晶须与树脂接触及浸润,然后与树脂间形成新的塑性界面层,在应力作用下,塑性界面层能发生形变以缓解应力集中,使得复合材料能吸收较大能量,从而使复合材料的韧性得以增强。碱式硫酸镁晶须和氢氧化镁晶须的最终分解产物为氧化镁和水,水蒸气的产生可吸收大量的热量和冲淡氧气的浓度,其分解产物氧化镁是优质耐火材料,可覆盖于聚合物表面阻止氧气和热量的进入,故能起到阻燃作用。本项研究成果对于碱式硫酸镁晶须和氢氧化镁晶须的规模化生产及应用具有一定的指导意义。更多还原

【Abstract】 As important inorganic materials with reinforcement and fire-retardant effects,basic magnesium sulfate and magnesium hydrate whiskers were widely applied in various fields such as plastics,chinaware,dope,metal,chemical,aviation spaceflight and so on.However,such products were still in the stage of research and development in China.Compared to the United States and Japanand other developed nations,our country had a large gap.In view of this situation,this paper researched the preparation,modification and application of both basic magnesium sulfate and magnesium hydrate whiskers on the base of previous studies.Took magnesite as row material and calcinated it for 3 hours at 700℃,basic magnesium sulfate whiskers were prepared by hydrothermal synthesis method with the activity magnesia for 4.0% of slurry,the reaction temperature of 200℃,the reaction time of 4 hours,and the stirring speed of 400r/min.Took sodium hydroxide and basic magnesium sulfate whiskers as raw materials,magnesium hydrate whiskers were prepared by hydrothermal synthesis method with the basic magnesium sulfate whiskers for the 4.0% of slurry,the reaction temperature of 180℃,the reaction time of 4 hours,the stirring speed of 100r/min,and equivalent weight ratio of sodium hydroxide to magnesium sulfate whiskers for 1.4:1.By means of single factor tests,basic magnesium sulfate and magnesium hydrate whiskers were modified by surface modification agents such as fatty acid,titanate,silane, aluminum esters and so on.The experimental results indicated that sodium stearate and zinc stearate were the most excellent modifiers for basic magnesium sulfate whiskers and magnesium hydrate whiskers individually.The contact angle,the activate index and the oil-adsorbed value of modified basic magnesium sulfate and magnesium hydrate whiskers were 111.85°,99.28%,186ml/100g and 126.38°,99.05%,354ml/100g respectively. The dispersion and fluidity of whiskers had evident improvement.Apart from the physical absorption,there were firmly chemical adsorption between the surface of whiskers and stestic acid salts.Added the modified basic magnesium sulfate and magnesium hydrate whiskers to polypropylene,the impact strength and the oxygen index increased and the tensile strength and the elongation at break decreased of both MOS/PP and MH/PP composite materials with addition of whiskers.The impact strength,the tensile strength, the elongation at break and the oxygen index of PP were 62J/m,25.8MPa,83.5% and 19.2%.When the increasing amount is 50%,these indicators of MOS/PP composite were 79.67J/m,20.6 MPa,9.7% and31.5%,and these indicators of MH/PP composite were 75J/m,21MPa,7.2% and 32.8%.Integration mechanics property and fire-retardant property of composite increased.In this paper,basic magnesium sulfate and magnesium hydrate whiskers toughness and flame retardant action mechanism for polypropylene were researched.The results indicated that the surface of whiskers and resin formed a new plastic interface layer after contacting and infiltrating,when the stress did its work,the plastic interface layer could deform to alleviate stress concentration and make composite system absorb more energy,so that the toughness of composite material can be enhanced.The final decomposition products of them were magnesia and water. The water could absorb a large amount of calories and dilute the concentration of oxygen.The magnesia was a nicer fireproof material which can cover the surface of polymer so as to prevent the entry of oxygen and heat,so it could serve the purpose of fire retardant.Achievements in this paper had a certain guiding significance for the large-scale production and application of basic magnesium sulfate and magnesium hydrate whiskers.更多还原