【作者】 王大鹏；

【导师】 赵树高；

【作者基本信息】 青岛科技大学 ， 高分子化学与物理， 2009， 硕士

【摘要】 本文研究了塑料基体、偶联剂、润滑剂以及加工过程对挤出、注射成型制备的聚酰胺6(PA6)粘结铁氧体体系结构与性能的影响。首先,在不同工艺条件下制备出粘结磁体,然后使用双毛细管流变仪、差示扫描量热仪、扫描电镜、拉力机等仪器,分析了不同改性方法、偶联剂的类型及其用量、润滑剂的类型及其用量以及干燥过程对粘结磁体的流变性能、力学性能和微观形态的影响。实验结果表明:PA6及PA6/PA610(聚酰胺610)共混体系,在熔融流动过程中,特别是在高剪切速率阶段符合对数律,并且发现该体系的拉伸粘度(ηe)与剪切速率的平方除以拉伸速率(t)存在着精确的ηe ~1/t关系。铁氧体/PA6复合物的非等温结晶行为与铁氧体含量、偶联剂和冷却速率密切相关。掺入PA6基体中铁氧体颗粒的效应有:1)作为物理阻碍物阻碍了晶核形成并降低了结晶速率;2)由于磁粉与PA6之间的不相容性,导致在相界面上存在缝隙,使结晶活化能降低,结晶容易发生,在低磁粉填充量阶段反而有利于结晶。磁粉经硅烷偶联剂KH-792处理后,作为异相成核剂,导致结晶速率和结晶度的增加。将磁粉表面使用偶联剂包覆,可以显著地改善聚合物基体和磁粉之间的相容性,提高界面结合能力,宏观上表现为增进粘结磁体的机械性能。表面处理工艺也会提高磁粉在基体中的分散,提高了粘结磁体熔体的加工稳定性。由于界面结合力增强,使得粘结磁体熔体粘度增大,熔体流动稳定性增强,可以稳定的工业化制备性能均一的粘结磁体产品。更多还原

【Abstract】 The influence of polymer matrices, coupling agents, lubricants and processing technology on the structure and properties of polyamide 6 (PA6) bonded ferrites fabricated by extrusion/injection molding were systematically studied in this paper. At first, the bonded magnet has been obtained under various technological conditions. Then, the influence of these conditions, such as the modified methods of polymer matrices, types and contents of coupling agents, types and contents of lubricants, and processing technology on the rheological, mechanical and micro-structural properties of PA6 bonded ferrites were investigated using modern apparatus such as high pressure capillary rheometer, scanning electron microscope (SEM), differential scanning calorimetry (DSC) and tensile testing machine etc. The results indicated that,It was found that rheological data of PA6 and PA6/PA610 blends fit well with the logarithmic law during the shear flow, especially in the high-shear-rate region. What was more, extensional viscosity obtained precise mathematical relationship with squared shear rate divided by extensional rate during the extensional flow of PA6 and PA6/PA610 blends.There were significant dependence of non-isothermal crystallization behavior and kinetics of ferrite/PA6 composites on the ferrite concentration, coupling agent and cooling rate. The effect of ferrites into PA6 matrix was: 1.the presence of ferrite the PA6 matrix act as physical obstacles hindering the nucleation and decreasing the crystallization rate; 2. due to strongly incompatibility between ferrites and PA6 matrix, there were some cavities on the phase interface which decreased the crystallization activation energy and further ease the crystallization process. However, the ferrite treated with silane coupling agent KH-792 in the PA6 matrix acting as heterogeneous nuclei, resulted in increasing the crystallization rate and degree of crystallinity, due to hydrophobic interfacial property.Incorporation of coupling agents onto the surface of ferrite powder could significantly improve the compatibility between polymer matrix and magnetic powder, which caused the interfacial adhesion stronger, thus further improved the mechanical properties. Surface treatment also improved the dispersion of magnetic powder in polyamide matrix, further enhanced the processing stability of the compound. The enhanced interfacial adhesion was correlated with higher viscosity and with stronger flow stability of bonded magnets material, for the potential industrial products with long-term stable performance.更多还原