【作者】 吴湘锋；

【导师】 王标兵；

【作者基本信息】 中北大学 ， 材料学， 2008， 硕士

【摘要】 近年来随着人们环保意识的增强及阻燃法规的相继颁布，对环境的影响已成为聚合物选择阻燃剂的一个重要因素。由于超细氢氧化镁[Mg(OH)2]具有一系列卓越的性能，符合可持续发展战略，日益成为人们研究的热点。然而大多数Mg(OH)2的制备方法工艺流程长、成本高、效率低或对设备要求高，产品过滤困难、粒径大且分布宽、团聚严重。特别是作为聚合物阻燃剂使用时，其团聚现象严重恶化了聚合物基体的力学性能。因此研制超细单分散的Mg(OH)2阻燃剂具有很高的实际应用意义。本论文以一种简单高效的方法制备出高纯单分散的超细Mg(OH)2，表征了产品的形貌、粒径及其分布。采用熔融共混的方法制备了增容PP/Mg(OH)2共混物，系统研究了共混物的阻燃效果、力学性能以及流变性能。本文首次以丙酮和氯化镁液的混合液为母液，在常温下采用卤水—氨正向加料直接沉淀法制备出高纯单分散超细Mg(OH)2疏松粉体。随着母液中丙酮含量的增加，产品的过滤时间、干燥时间、平均粒径、分散状况、团聚状况和聚集状态逐渐改善。当母液中丙酮含量为80%时，与母液中未加入丙酮相比，产品的过滤时间减少了98.9 %，干燥时间减少了79.2 %，微粒形貌为规则的圆片状（首次报道），平均粒径为382.7nm，呈单分散性，产品为非常疏松的粉末，不含NH4Cl·MgCl2·6H2O杂质。论文中采用“一步法”对Mg(OH)2进行表面处理，亦即在液相沉淀反应中氨水加料结束后2.5h继续添加基于六水氯化镁质量1.2%的硬脂酸，产品由“亲水型”转变为“疏水型”，“活化指数”达到100%。Mg(OH)2经表面改性后较未改性添加到聚丙烯中，复合材料的力学性能、Mg(OH)2的分散性和界面相容性得到改善，在其用量为90phr时极限氧指数达到27.5%，但与纯聚丙烯相比复合材料的力学性能急剧恶化，加入复合增容剂POE-g-MAH和EPDM-g-MAH、碳酸钙和新型无卤阻燃剂六苯氧基环三磷腈（POP），复合材料的力学性能和阻燃性能显著得到改善。在Mg(OH)2用量为42phr，复合增容剂（POE-g-MAH和EPDM-g-MAH的质量比为1：1）用量为15phr，碳酸钙用量为40phr，六苯氧基环三磷腈用量为8phr时复合材料断裂伸长率、拉伸强度、冲击强度分别达到264.76%、22.34MPa、48.65 KJ·m-2，同时极限氧指数可达28.2%。流变测试结果表明，复合增容剂和碳酸钙的加入并没有改变共混体系的非牛顿型假塑性特征，表现出明显的“切力变稀”现象。更多还原

【Abstract】 Recently, influence on environment was an important consideration for the selection offire-resistant in the polymer with the enhanced protection consciousness of people andconsequent promulgation of the laws and regulations about fire -retardant all over the world.For its series excellent merits as well as in agreement to the sustainable development strategy,superfine magnesium hydroxide was increasingly developed. However, most of the currentprocessing methods of magnesium hydroxide had deficiency, for example, long technologicalprocess, high yield cost, exorbitant equipment, difficult filterability, large size and broad sizedistribution, and serious aggregation. Especially, when magnesium hydroxide was blendedwith polymer, its serious aggregation deteriorated the mechanical performances of thepolymer matrix. Therefore, the prapration of superfine and monodispersion magnesiumhydroxide is more practable. In this dissertation, superfine and monodispersion magnesiumwith high purity was prepared via an easy and high efficient. The particle size and itsdistribution, morphology, crystal phase, and thermal behavior of the product werecharacterized through ultrasonic particle size analyzer (UPSA), transmission electronmicroscopy (TEM) and scanning electron microscopy (SEM), X ray diffraction (XRD),Fourier transform-infrared spectroscopy (FT-IR), and thermogravimetry (TG), respectively.Compatibilized PP/Mg(OH)2 blends were prepared by melting compounding, and thefire-resistance, mechanical and rheological properties were investigated.Superfine magnesium hydroxide was synthesized by using magnesium chloridehexahydrate in presence of acetone as precursor and industrial ammon ia as precipitator in thisdissertation. The filtering time, drying time, mean grain size, dispersivity and aggregationwere gradually improved with increasing content of acetone in the mother liquor. In comparison with blank experiments, the filtering time and drying time were drasticallydecreased by 96% and 75% at the level of 80% acetone in the mother liquor, disk-like andmonodispersed ( d 314nm) magnesium hydroxide particles with high purity (that is, impurityof NH4Cl MgCl2 6H2O not to be examined in the products) were obtained.One-step method was adopted to treat the surface of magnesium hydroxide. Namely,1.2 wt% stearic acid of magnesium chloride hexahydrate was added at the time 2.5h after theend of feeding ammonia. The surface property of products was completely translated fromhydrophilicity to hydrophobicity, and the hydrophobicity index of products was up to 100%.Mechanical properties, dispersibility of magnesium hydroxide and interfacial compatibilityof polypropylene/magnesium hydroxide blends were obviously improved when magnesiumhydroxide was surface-treatment. The oxygen index was 27.5% in the case of 90phrmagnesium hydroxide. However, the mechanical performances of blends were seriouslydeteriorated by contrast to pure polypropylene. The Mechanical and fire-retardant propertieswere obviously improved after the addition of hybrid compatibilizer (POE-g-MAH andEPDM-g-MAH), calcium carbonate and halogen-free fire retardant (POP). Elongation atbreak, tensile strength, impact strength and oxygen index of composites was 264.76%,22.34MPa, 48.65 KJ m-2 and 28.2% at the level of 42phr magnesium hydroxide, 15phrhybrid compatibilizer, 40phr calcium carbonate and 8phr POP. The rheological resultsindicated that the addition of hybrid compatibilizer and calcium carbonate did not change theNon-Newtonian pseudoplastic character of blends and all blends displayed theshear-thinning phenomenon.更多还原