【作者】 丁胜春；

【导师】 李侃社；

【作者基本信息】 西安科技大学 ， 矿物加工工程， 2009， 硕士

【摘要】 聚氯乙烯是最早实现工业化的塑料品种之一,但其韧性差,因此需要对PVC进行增强、增韧改性,以期得到高性能的PVC复合材料。高岭土作为一种无机填料,以资源丰富、价格便宜等优势广泛应用于聚合物的填充改性。本文采用插层-膨胀-爆炸法成功制得纳米高岭土。先将醋酸钾小分子插入高岭土层间,使高岭土层间距膨胀扩大,再在400℃下醋酸钾高温分解为CO2和水蒸气,以气体爆炸的形式实现片层剥离制得纳米高岭土。讨论了醋酸钾用量、插层时间、水用量对插层率的影响,优化出插层方案:醋酸钾与高岭土质量比为1:1、插层时间为24小时、水用量为10%时,插层率高达90%。通过XRD、FTIR、粒度分析、扫描电镜等表征了高岭土-醋酸钾复合物和纳米高岭土的微观结构、粒度分布和形貌特征。用偶联剂对纳米高岭土进行改性,表观现象观察、萃取实验、FTIR及改性前后吸油值的变化表明,偶联剂与高岭土表面发生了化学键接,偶联剂不仅改变了高岭土表面性能,也改变了颗粒内和颗粒间的空隙。根据配方将改性后的高岭土、PVC、其它助剂均匀混合,在开放式炼胶机上实现了PVC与高岭土的共混填充,制备了PVC/高岭土复合材料,并对复合材料的力学性能进行了测试。讨论了高岭土用量、偶联剂用量及种类、稳定剂用量和增塑剂用量对体系力学性能的影响。通过实验优化出最佳配方:高岭土含量8%、偶联剂用量2.0%、稳定剂用量2.0%、增塑剂用量10%。此时材料的拉伸强度达54 MPa,断裂伸长率为120%,无缺口冲击强度为43 kJ/m2。热重分析证明复合材料的热稳定性远优于PVC材料:材料起始失重温度由120℃提高到150℃。SEM表明复合材料断面的断裂形式发生了质的转变:由脆性断裂转变成韧性断裂。改性后的高岭土起到了增强、增韧的双重作用,达到了预期效果。更多还原

【Abstract】 Polyvinyl-chloride is one of the earliest industrialization plastic varieties, but it is brittle. Therefore, it is necessary to carry on the studies of reinforcing and toughening modification to obtain PVC composite with high performances. As a kind of inorganic filler, Kaolin is applied to polymer modification widespread because of rich resource, cheap price and other advantages.Nano-Kaolin was prepared by intercalation layer-swelling-explosion method. Firstly inserting the potassium acetate small molecular to the Kaolin interlayer, which enlarged Kaolin layer-space by swelling, Secondly, pyrolyzing potassium acetate into CO2 and steam under 400℃, nano-Kaolin could be obtained by this gas explosion force. The effect of potassium acetate content, intercalation time, water content on intercalation ratio were discussed and the best conditions were optimized: When weight ratio of potassium acetate with Kaolin was 1, intercalation time was 24 hours, the water content was 10%, intercalation ratio was the best, reaching as high as 90%. The micro-structure, particle size distribution and morphology characteristic of Kaolin-potassium acetate intercalation compound and nano-Kaolin were characterized by X-ray Diffraction, Fourier Transform Infrared Spectra, Particle Size Analysis, Scanning Electron Microscope.Kaolin was treated by coupling agents. It was indicated by apparent phenomenon observation, extraction experiment, FTIR and oil adsorption value’s change that coupling agent and Kaolin surface occurred chemical invigorate connection, coupling agent not only changed the Kaolin surface performance, but also changed Kaolin’s particle inter-space among internal and inter.Mixing modified Kaolin with PVC and other additives according to formula uniformly, the blending and filling of PVC and Kaolin was realized on opened refine rubber machine. PVC/Kaolin composites were prepared and their mechanical properties were tested. The influence of Kaolin content, coupling agent content and type, the stabilizer content and the plasticizer content on mechanical properties were discussed and the best formula was optimized : When Kaolin content was 8%、coupling agent was 2.0%、the stabilizer was 2.0%、the plasticizer was 10%, mechanical performance of the composites was the best. The material tensile strength reached 54MPa, elongation at break reached 120%,unnotched impact strength reached 43kJ/m2. It was indicated that thermal stability of the compound was obviously superior to the pure PVC material by TG analysis: material initial weightlessness temperature improved from 120℃to 150℃. The break form of the material’s cross section happened qualitative transformation by SEM: from brittle fracture transformed into ductile fracture. Modified Kaolin had played dual function of reinforcing and toughening, the anticipant results were achieved.更多还原