【作者】 胡纯；

【导师】 龚文琪； 孙振亚；

【作者基本信息】 武汉理工大学 ， 矿物加工工程， 2005， 硕士

【摘要】 本文通过以一定比例热稳定性好的纳米-亚微米矿物重晶石和纳米SiO2作为填充料,经机械力化学改性处理,制备出热学性质优越的矿物复合改性酚醛树脂纳米复合材料。研究了所制备的酚醛树脂纳米复合材料的结构和热稳定性能,并且研究了以自制酚醛树脂纳米复合材料为基体的刹车片摩擦材料摩擦磨损性能。结果表明:由于纳米-亚微米矿物重晶石和纳米SiO2粒度小、比表面积大、表面非配对原子多、表面化学活性高,因而与酚醛树脂结合能力强,并可对酚醛树脂的物化性能产生特殊影响。矿物可抑制有机物的热分解,大幅度提高酚醛树脂的热分解温度,其热分解初始温度由187℃提高到206. 3℃,树脂分子快速分解阶段的起始温度由362. 6℃提高到394. 7℃。自制的酚醛树脂/矿物纳米复合材料用作摩擦材料的粘结剂,摩擦材料的摩擦磨损性能有显著改善,刹车片的摩擦系数稳定,高温下磨损率小,有效地避免了摩擦磨损性能的热衰退,扩大了高温制动条件范围。该研究对于高速制动材料的开发具有较大意义。本文还探索了与目前高分子的插层聚合、溶液插层和熔融插层等方法不同的制备聚合物/粘土纳米复合材料的方法,首次采用静高压方法成功制备了酚醛树脂/累托石纳米复合材料。并且通过XRD、FT-IR、TEM、AFM和TGA等测试手段对所制备的纳米复合材料的微观结构和性能进行了表征和研究。研究表明:采用静高压方法可以使酚醛树脂分子在相对较低的压力下插入累托石粘土层间,使得粘土片层层间距由2～3 nm扩大到5～6 nm,形成插层型纳米复合材料,在更高压力下插层至剥离型纳米复合材料,并且复合材料中累托石比例含量在较低(4%)和较高(20%)的情况下均可通过高压方法形成纳米复合材料。另一方面,由于高压下制备的聚合物/粘土纳米复合材料是将聚合物大分子直接插入粘土层间,未产生聚合固化反应,复合材料仍为粉体材料,这为进一步研究粘土晶层间的结构及其性质提供了有效途径。并且由于粘土片层与酚醛树脂分子得到很好的复合,高压作用并未破坏酚醛树脂/累托石纳米复合材料中酚醛树脂分子的结构,使得纳米复合材料的耐热性有了很大的提高,为酚醛树脂在更高温度领域的应用提供了可能。此方法在探索聚合物/粘土纳米复合材料的制备方面有着巨大的创新意义。更多还原

【Abstract】 In this paper, phenolic resin/mineral nanocomposites with excellent thermal properties were prepared with a certain proportion of nanometer and submicron barite minerals and nanometer SiO₂ that had good thermal stability as the filler and by mechano-chemical modification. The distribution of the nanometer-sized particles in the resultant materials, thermal stability and other corresponding properties were characterized. Moreover, the friction and wear performance of the brake pad based on the developed nanocomposites was also investigated. The results indicated that due to small particle size, large specific surface area, many non-paired surface atoms, and high surface chemical activity, the minerals have strong bonding with phenolic resin and have made special influence on the physicochemical properties of phenolic resin. Nanometer and submicron minerals can restrain thermal decomposition and raise the thermal decomposition temperature of phenolic resin substantially. The self-made nanometer and submicron mineral modified phenolic resin was used as the binder of the automobile frictional material. The nanocomposites meet the standard of the phenolic resin used in frictional materials. Compared to the brake pad based on phenolic resin, the wear rate of the present one with phenolic resin/mineral nanocomposite decreased obviously, especially at high temperature. In addition, the wear performance of the brake pad based on phenolic resin/mineral nanocomposites was also improved. A preferential stable friction was achieved for a brake pad based on nanocomposites, which can be used as a high performance frictional material.In this paper, different from the preparation methods of polymer/clay nanocomposites including intercalation polymerization,polymer solution-intercalation and polymer melt-intercalation, high-pressure method was used for the first time to produce phenolic resin/rectorite clay nanocomposites. In the mean time, the microstrutures of the clays and the nanocomposites were characterized by XRD, FT-IR, TEM, AFM and TGA techniques. The results show that the polymer molecules entered the interlayers of the clay under high pressure, resulting in intercalated nanocomposites under ralatively lower pressure and exfoliated nanocomposites under higher pressure. When the proportion of rectorite was 4% or 20%, nanocomposites can form under high pressure. On the other hand, without polymerization solidification reaction, the preparation of polymer/clay nanocomposites made the polymer molecules enter the interlayers of the clay under high pressure. Socomposites were still powder material, which has offered an effective way for further studies on the structure of clay layers. Because the thermal property of nanocomposites has been improved greatly, it is obvious that nanocomposites have greater thermostability. It provides possibility of application of phenolic resin in the fields of high temperature.更多还原