聚合物乳液法表面修饰改性Fe_3O_4磁性纳米粒子特性研究

探讨了一种聚合物乳液在机械搅拌下,改性修饰Fe3O4纳米粒子表面,制备Fe3O4-聚合物复合粒子的方法。含羧基基团的柔软的聚合物乳胶粒子在机械搅拌作用下,与Fe3O4纳米粒子碰撞,变形,并通过物理粘附及羧基活性基团的化学吸附作用来包覆Fe3O4纳米粒子。在透射电子显微镜下可看到Fe3O4粒径约为5~20 nm,被聚合物包覆,虽存在团聚,但团聚体尺寸也仅100 nm左右,且团聚体中的Fe3O4纳米粒子也为聚合物隔开,纳米粒子得到了良好的分散。通过红外、热失重、接触角等的测试分析,进一步证实乳液聚合物对Fe3O4纳米粒子实现了表面修饰。实验结果表明,改性用聚合物的Tg以及复合温度是影响聚合物对Fe3O4纳米粒子包覆的重要因素之一。

The Modification Method and Property of Fe3O4 Nanoparticles Treated by Polymer Emulsion

The method of modifying the surface of Fe_3O_4 nanoparticles and forming polymer-Fe_3O_4 composites was investigated.Emulsion of some soft polymer with carboxyl group was designed and prepared in advance,and then magnetite(Fe_3O_4) nanoparticles were treated by this kind of polymer emulsion through physical adsorption and chemical absorption of carboxyl group under stirring.During the process,softened emulsoids lose their intrinsic shapes and are absorbed on the surface of the nanoparticles.TEM pictures show clearly that the diameters of Fe_3O_4 nanoparticles are about 5～20 nm,and the nanoparticles are covered by polymer.The aggregated situation of Fe_3O_4 is meliorated obviously.Although there are still aggregates of Fe_3O_4,but the Fe_3O_4 particles are separated by polymer already and the sizes of aggregates are about 100 nm only.In addition,the composite particles were characterized by IR,TGA,and contact angle,which evidenced further the composite structure of polymer-Fe_3O_4.According to the experiment,during the process of compounding,T_g of the polymer and the compounding temperature are the important factors to affect the surface modification of nanoparticles.