【作者】 张育民；

【导师】 仲剑初；

【作者基本信息】 大连理工大学 ， 化学工程与技术， 2011， 硕士

【摘要】 硼酸钙是一种重要的化工原料和产品,可广泛应用于玻璃、油漆、钢铁、陶瓷等行业。此外,还可应用于阻燃剂、非线性光学材料、农业、防腐剂以及医药等领域。基于对硼酸钙物化特性的考察,为了拓宽其应用范围力求开发出一种质优价廉的无卤阻燃剂,本文对硼酸钙表面极性进行了有机化修饰,从而改善矿物填料与有机聚合物的亲合性、相容性,提高有机复合材料的机械性能,增加填充量,降低生产成本,扩大矿物填料的应用领域,提高矿物填料的工业价值和经济价值。本文以硼酸和氢氧化钙为原料,通过水热合成考察了各工艺条件对合成硼酸钙类型、粒度及产率的影响；通过对合成产物进行化学成分、XRD、TG、FT-IR、SEM、粒度分布等表征分析,确定硼酸钙生成的类型、失重温度、及颗粒分布等物理化学信息,为硼酸钙阻燃剂的筛选提供有用的信息。水热反应合成白硼钙石的适宜条件为：在160℃、原料B2O3／CaO摩尔比为1.7、液固比为6时,反应4小时,可获得单一物相的白硼钙石。合成的白硼钙石在110-600℃范围内失重约17.40%,对应连续脱除7个水分子,在200℃之前,失重小于2%,产品的平均粒径5.96μm,粒径主要分布在3-8μm范围内。在水热合的成产物白硼钙石基础上,以硬脂酸钠为改性剂对白硼钙石进行湿法改性,考察了工艺条件对白硼钙石湿法改性的影响；此外,利用合成改性一步完成的方法,考察了硬脂酸钠的用量对产物的改性效果。结果表明：湿化学法改性白硼钙石的适宜工艺条件为：改性时间75min,改性温度80℃,改性的硬脂酸钠用量5%,改性的液固为3(mL／g)时,得到的改性产物的活化指数为97.16%,接触角为125.55°；一步法得到的改性白硼钙石活化指数测得的结果表明,硬脂酸钠的用量在4%时比较适宜,活化指数达到86.80%,接触角为104.9°。对土耳其硬硼钙石进行了化学分析,并用X射线衍射、热重分析、离心粒度分析等方法对其进行了表征。考察了土耳其硬硼钙石的球磨前后,不同改性剂及改性方法等因素对改性效果的影响。结果表明：在湿法改性中,硬脂酸钠的用量为2%,80℃下,液固比为2：1,改性75min时,原料球磨前与球磨后,改性得到的活化指数分别为45.95%和64.95%,对应的接触角为别129.3°和112.7°。实验还采用NDZ-311溶液对土耳其硬硼钙石进行机械化学法球磨,得到产物活化指数为67.85%,对应接触角为85.6°并对其改性的机理做了初步的探讨。本文还对两种改性硼酸钙单独在乙烯—醋酸乙烯酯中进行了添加并对测试了其力学性能,简单讨论了产物燃烧的情况和残渣的微观结构。更多还原

【Abstract】 Calcium borate (xCaO·yB2O3·nH2O) is one of the important chemical materials and products. It can be widely used in glass, paint, steel, ceramics industries, etc. In addition, it also can be applied in flame retardants, nonlinear optical materials, agricultural, antiseptic and medicine industries, etc. The synthesis of calcium borate depends on many conditions, such as raw materials, pH value, process route, etc. In order to develop caicium birate as a high-quality halogen-free flame retardants with less cost, the superficial polarity features of calcium borate should be modified based on its physical and chemical characteristics. The affinity and compatibility of calcium borate with polymer minerals would be improved when modifying calcium borate and the mechanical properties of polymer materials can also be enhanced when adding modified calcium borate. With the filling of the modified calcium borate into the organic materials, the production cost of polymer minerals can be reduced and the application field of calcium borate can be also widened. In addition, the industrial value and economic value of calcium borate is expected to rise.In this paper, calcium borate was synthesized with using boric acid and calcium hydroxide as raw materials by a hydrothermal synthesis, the influences of raw material ratio, solid to liquid ratio, reaction time and reaction temperature on the type, particle size and yield of calcium borate were studied, respecyively. The perferred reaction conditions were acquired. Calcium borate obtained by hydrothermal synthesis was characterized by XRD, TG/DTG, SEM, chemical analysis and particle size distribution analysis. Many useful physics and chemistry information, such as the type of calcium borate synthesized, temperature of weight loss, the distribution of particles size, were provided for screening a proper flame retardant. The suitable synthesis conditions are as follows:reaction temperature 160℃, raw materials’ B2O3/CaO molar ratio 1.7, liquid to solid ratio 6 and reaction time 4h. Pure preceite was synthesized under these conditions. The contents of B2O3 and CaO in the synthesized preceite are 47.65wt% and 30.41wt%. The weight loss of preceite is about 17.40% between 110 and 600℃, indicating removing 7 water molecules, and the weight loss of preceite is less than 2% before 200℃. The average particle size of preceite is about 5.96μm and particle size distribution is mainly between 3 and 8μm。The priceite was modified using sodium stearate as a modification reagent by a wet chemical process. Effects of temperature, time, surfactant addition and liquid to solid ratio on the modification of priceite were discussed. In addition, modified priceite was evaluated by FT-IR, SEM, contact angle, activation index and suspension performance in water. The preferred modification conditions for priceite was achieved when priceite was treated at 80℃for 75min with a liquid to solid ratio of 3 by adding 5wt.% of sodium stearate. The activation index of the modified priceite can reach to 97.16% and the contact angle of the modified priceite is up to 121.23°. In addition, the process for the modified priceite with one-step hydrothermal synthesis/surface modification was also discussed. The activation index of the modified priceite can reach to 86.80% and the contact angle of the modified priceite is 104.9°with 4.0wt.% of sodium stearate addition.The colemanite of Turkey was characterized by chemical analysis, XRD, TG/DTG and particle size distribution analysis. The raw colemanite, ball milling colemanite, different modifiers and different modification method were investigated in the process of modification. The modified products were characterized by FT-IR, contact angle, activation index and SEM. Results showed that when the colemanite was treated at 80℃for 75min with a liquid to solid ratio of 2 by adding 2.0wt.% of sodium stearate, the activation indexes of modified raw colemanite and modified ball milling colemanite were 45.95%, with a contact angle at 129.3 0 and 64.95%, with a contact angle at 112.7°, respectively. The activation index of colemanite modified by NDZ-311 with ball milling was also reached to 67.85%, with a contact angle at 85.6°. In addition, the modification mechanism was also discussed. The modified calcium borates were filled into EVA, and the mechanical properties of the composite materials were tested. The composite materials were then burned and surface morphologies were observed by microscope.更多还原