【作者】 王铮；

【导师】 仲剑初；

【作者基本信息】 大连理工大学 ， 化学工艺， 2012， 硕士

【摘要】 偏硼酸钙(CaO·B2O3·nH2O)是一种常见的无机硼化合物,其主要应用于无碱玻纤、油漆涂料加工、陶瓷制造、阻燃材料等行业。阻燃剂型偏硼酸钙添加在高聚物中当作阻燃剂使用时,由于其表面极性的不利影响,使其与有机化合物的相容性偏低,需对作为无机填料使用的偏硼酸钙表面极性进行有机化修饰,改善其与有机聚合物的亲合性和相容性,增加不同材料复合后呈现的机械性能。本文正是在这一背景下,采用两种不同的改性方法,以偏硼酸钙为改性对象,利用适宜的改性剂对偏硼酸钙进行表面修饰和改性,以期改善其表面性质,提高其应用价值和经济价值。在室温下以硼酸与氢氧化钙为原料合成六水偏硼酸钙,获得的六水偏硼酸钙在140℃下干燥3h,脱除结晶水获得无定型二水偏硼酸钙。通过对合成产物及干燥产物进行的化学成分分析(化学滴定)、X射线衍射分析(XRD)、热重分析(TG-DTG)和粒度分析,获得了产物的组成、物相、二水偏硼酸钙的失重温度及颗粒粒度分布等化学物理性质,为二水偏硼酸钙作为阻燃剂使用和表面改性提供了有用信息。六水偏硼酸钙经过热处理,得到的二水偏硼酸钙为无定型粉体,产品的平均粒径24.16μm,产品的粒径主要集中在20-30μm之间；在100℃之前失重小于3.5%,在100-600℃范围内失重约22%,对应连续脱除两个水分子。在此基础上,分别以硬脂酸钠和油酸作为湿法表面改性的改性剂,对二水偏硼酸钙进行表面改性处理,考察了改性剂(硬脂酸钠和油酸)加入量、湿法改性时间、湿法改性的温度等反应条件对二水偏硼酸钙湿法改性的影响,对改性产物进行了红外光谱分析(IR)、活化指数、接触角、扫描电镜(SEM)等分析表征。结果表明硬脂酸钠湿化学法改性二水偏硼酸钙的最佳工艺条件为：改性时间60min,改性温度60℃,改性剂硬脂酸钠用量5%,得到的改性产物的活化指数为95.27%,接触角为106.3。。油酸湿化学法改性二水偏硼酸钙的最佳工艺条件为：改性时间90min,改性温度90℃,改性剂油酸用量为5%,得到的改性产物的活化指数为95.79%。本文还分别以硬脂酸钠和油酸为改性剂,对偏硼酸钙合成和改性一步完成的工艺方案进行了考察研究。在六水偏硼酸钙合成时,同时加入改性剂硬脂酸钠或油酸,考察了改性剂的用量对产物改性效果的影响。在硬脂酸钠用量为3%时,硬脂酸钠合成改性一步法得到的改性二水偏硼酸钙活化指数和接触角分别为：活化指数99.77%,接触角为109.6°。在油酸的用量在2%时,油酸合成改性一步法得到的改性二水偏硼酸钙活化指数达到了93.94%。在添加相同量改性剂的条件下,一步法改性效果明显优于二步法,同时简化了合成改性步骤,节约改性成本。此外,对上述二水偏硼酸钙的改性机理也进行了初步的探索研究。更多还原

【Abstract】 Calcium metaborate (CaO·BaO3·nH2O) is a kind of important boron compound, mainly used in alkali-free fiberglass, paint, ceramics, flame retardant and so on. Calcium metaborate can not be well compatible with polymer because of its surface polarity when adding it in polymer as a flame retardant. Therefore, calcium metaborate should be modified by using organic modifier in order to improve its compatibility with organic polymer and enhance the mechanic properties of organic-inorganic composite materials. In this paper, two kinds of different modification processes for calcium metaborate were investigated and several modifiers were employed to modify calcium metaborate in order to improve its surface polarity.In this paper, the reaction of boric acid with calcium hydroxide afforded calcium metaborate hexahydrate at the room temperature. Then, calcium metaborate hexahydrate was dried at140℃for3h to form calcium metaborate dihydrate (CaO·B203·2H20). The obtained products were characterized by chemical analysis, XRD, TG and particle size distribution analysis, some useful information on products, such as composition, phase, losing weight temperature and particle size distribution, were obtained. The XRD result indicated that the afforded calcium metaborate dihydrate was amorphous, and the particle size distribution of the product ranges from20μm to30μm, and the average particle size is24.16μm. The weight loss of calcium metaborate dihydrate is about22%within the range of100-600℃, indicating the removal of two water molecules. Before100℃, the weight loss of calcium metaborate dihydrate is less than3.5%. In order to make the synthesized calcium metaborate dihydrate have a good compatibility with polymer materials, surfactant was used to modify the product by a wet chemical process. Sodium stearate and oleic acid were selected as modification reagents, respectively. The influences of temperature, time, and adding amount of surfactant on the modification of calcium metaborate dihydrate were discussed and the modified calcium metaborate dihydrate was evaluated by FT-IR, contact angle and activation index. The modification result for calcium metaborate dihydrate indicated that the activation index and contact angle of the modified calcium metaborate dihydrate are95.27%and106.3°when10g of calcium metaborate dihydrate was treated at60℃for60min by adding0.5g of sodium stearate, while lOg of calcium metaborate dihydrate was treated at90℃for90min by adding0.5g of oleic acid, the activation index of the modified calcium metaborate dihydrate are95.79%.In addition, in contrast to the above mentioned two-step process, the process for the modified calcium metaborate dihydrate with one-step synthesis/surface modification was also discussed. The activation index of the modified calcium metaborate dihydrate can reach to99.77%and the contact angle of the modified calcium metaborate dihydrate is109.6°with3.0wt.%addition of sodium stearate, while the activation index of the modified calcium metaborate dihydrate can reach to93.94%with2.0wt.%addition of oleic acid. It is noted that the modification effect of one-step process for calcium metaborate dihydrate is better than that of two-step process. The brief modification mechanism was also discussed.更多还原