【作者】 李胜利；

【导师】 田玉美；

【作者基本信息】 吉林大学 ， 物理化学， 2011， 硕士

【摘要】 硼酸锌是一种工业上常用的无机阻燃剂。它具备无机阻燃剂特有的优点：热稳定性好、不挥发、不析出、不产生有毒气体等。另外,硼酸锌还具备抑烟、积炭、与其他阻燃剂共掺能起到阻燃增效的特点。为了提高硼酸锌在聚合物中的阻燃效果,主要有两大途径：一是硼酸锌的纳米化。这是为了能提高硼酸锌与聚合物之间的接触面积,更好的发挥其阻燃效果。二是硼酸锌的表面改性。硼酸锌与聚合物之间相容性差,通过表面改性,提高硼酸锌与聚合物的相容性。最大程度地避免硼酸锌掺到聚合物中对其物理—机械性能的破坏。本论文主要采用两种方法合成硼酸锌：一是利用硼酸与氧化锌为原料合成出了工业上常用的2Zn0·3B2O3·3.5H20。要想得到粒度较小、形貌稳定的2ZnO·3B2O3·3.5H2O,反应条件应控制如下：温度在85℃以上,液固比为2.5以上,硼酸与氧化锌摩尔比大于3：1,反应时间在2h以上。通过上述条件可以得到厚度为100nm左右的多孔纳米片状硼酸锌。通过油酸对硼酸锌进行原位修饰,当油酸的添加量为2.0wt.%时,硼酸锌的接触角可以达到129°。二是利用硼砂、硼酸和硝酸锌为主要原料合成硼酸锌,通过控制反应的条件可以得到三种不同结构的硼酸锌(2ZnO·3B2O3·7H2O、3ZnO·3B2O3·5H2O、2ZnO·3B2O3·3.5H2O),实现不同种类硼酸锌的可控合成。本论文中对于硼酸锌阻燃性的研究是以氧化锌和硼酸为原料,以油酸作为表面活性剂制备出的疏水性纳米硼酸锌(2ZnO·3B2O3·3.5H2O)为阻燃添加剂,以低密度聚乙烯(PE)为基材,利用溶液共混法制备出硼酸锌/PE复合材料。通过TGA测试分析PE热稳定性的差异,来判断硼酸锌的阻燃效果。测试结果表明：修饰过的硼酸锌以2.0wt.%的比例掺杂到聚乙烯中,聚合物的初始分解温度由340℃提高到408℃以上。更多还原

【Abstract】 Zinc borate is a kind of widely used inorganic flame-retardant in industry. It has the following excellence that belongs to inorganic flame-retardant:the perfect thermal stability, no volatilization, no separating out and no toxicity. Otherwise, zinc borate promotes fume suppression and the expanding of char. While used with other kind of flame-retardants, its effect becomes better.In order to elevate the flame retardant performance of zinc borate in polymers, there are two methods. The first is reducing the granularity of zinc borate to the nano scale, which could increase the interface between zinc borate and polymers and make good use of the function of zinc borate. The second is the modifying the surface of zinc borate. Because of the poor compatibility between zinc borate and polymers, it is necessary to modify the surface of zinc borate. After that, it is possible to avoid the destroy of mechanical properties of zinc borate/polymers.In our research, we synthesized zinc borates using two ways. The first is that we had successfully synthesized the 2ZnO·3B2O3·3.5H2O using ZnO and H3BO3 as the stuffs. To get the pure nano 2ZnO·3B2O3·3.5H2O, the reacting conditions set as follows:the temperature should be higher than 85℃, and the molar ratio of boric acid and zinc oxide should be higher than 3:1, and the reaction time should be longer than 2h. The synthesized zinc borate displayed nanoflake morphology with particle size of around 100-200 nm, thicknesses less than 100 nm, and that there are some uniform mesopores in the particles and the diameter of the cavities is about 10 nm. To modify the surface of zinc borate, we used the oleic acid as the modifying agent. While the dosage of oleic acid was 2.0 wt.%, the water contact angle of zinc borate reached to 129°. The second synthesis method was that we use Na2B4O7·10H2O and Zn(NO3)2 as the reactants. By controlling the reacting conditions, we could get three kinds of zinc borates, that is,2ZnO·3B2O3·7H2O,3ZnO·3B2O3·5H2O and 2ZnO·3B2O3·3.5H2O.We also did some research about the synthesized zinc borate’s flame retardant. We chose the hydrophobic zinc borate (2ZnO·3B2O3·3.5H2O) as the experiment object, which synthesized using ZnO and H3BO3 as the reactants and oleic acid as the modifying agent. Through solution mixed method, we mixed the hydrophobic zinc borate (2ZnO·3B2O3·3.5H2O) in PE, getting zinc borate/PE composites. To test the flame retardant of hydrophobic zinc borate, we mainly used TGA to research the thermal stability of zinc borate/PE composites, getting the general assessment about the flame retardant of zinc borates. The test results indicted that, when the dosage of hydrophobic zinc borate in PE reached 2.0 wt.%, the decomposition on-set temperature would elevate from 340℃to 408℃.更多还原