马来酸单十八酯在PSt-Fe3O4磁性纳米复合材料制备中的应用

通过马来酸酐和正十八醇的单酯化反应合成了马来酸单十八酯，将其用作可聚合表面活性剂修饰于Fe3O4纳米粒子表面。利用超声波将表面修饰过的Fe3O4纳米粒子直接分散在苯乙烯中形成可聚合磁流体，通过引发自由基聚合反应制备了PSt-Fe3O4磁性纳米复合材料。利用FT-IR、XRD和TEM分别研究了Fe3O4纳米粒子用马来酸单十八酯表面修饰前后官能团变化、结晶形态以及在不同介质中的形貌和分散状况。结果表明，经马来酸单十八酯表面修饰后的Fe3O4纳米粒子保持了其原有的立方晶型，粒径在8~12 nm，在苯乙烯和聚苯乙烯基质中分散均匀。TGA和振动样品磁强计(VSM)分析结果表明，和相似聚合条件下制得的聚苯乙烯相比，制备的PSt-Fe3O4磁性纳米复合材料的热稳定性有一定程度的提高，常温下表现为超顺磁性。

Application of Monooctadecyl Maleate in the Preparation of PSt-Fe3O4 Magnetic Nanocomposite

Monooctadecyl maleate was synthesized by the mono-esterification of maleic anhydride and octadecanol, and used to surface-modify Fe3O4 nanoparticles as a polymerizable surfactant. Polymerizable magnetic fluid was obtained by dispersing Fe3O4 nanoparticles into styrene monomer with ultrasonic wave and PSt-Fe3O4 magnetic nanocomposite was prepared through free radical polymerization. The structure, crystallization status and dispersion status in different dispersion phases of modified Fe3O4 nanoparticles were studied by FT-IR, XRD and TEM. Results show that the Fe3O4 nanoparticles modified by monooctadecyl maleate with the size of about 8-12 nm are of typical Fe3O4 cubic spinel structure and can be uniformly dispersed into styrene and fixed in nanocomposite during the polymerization. Results of TGA and Vibrating Sample Magnetometry (VSM) indicate that the prepared PSt-Fe3O4 nanocomposites are superparamagnetic and show the improved thermal stability compared with polystyrene under the same polymerization condition.