固相剪切碾磨方法制备聚丙烯/钛酸钡高介电常数复合材料

采用固相剪切碾磨方法(S3M)制备高介电常数聚丙烯/钛酸钡复合材料。当钛酸钡体积分数φBaTiO3=0.50时,体系的介电常数由纯聚丙烯的2.3增加到108.7(1 kHz)。复合材料断面的SEM照片显示,粒径约100 nm的钛酸钡粒子均匀分散在聚丙烯基体中。复合粉体的SEM、TGA和FT-IR分析表明固相剪切碾磨产生的强大剪切、挤压、摩擦等作用在聚合物相引起多种复杂的物理及化学变化,聚合物粒径变小,粒子比表面积增大,表面能大幅增加,与具有较高表面活性的钛酸钡粒子形成较强的界面相互作用。

High-Dielectric-Constant PP/BaTiO3 Composites Prepared by Solid State Shear Milling

Solid state shear milling(S~3M) was successfully applied to prepare polypropylene(PP)/(BaTiO_3) nanocomposites potentially for dielectric applications.Scanning electron microscopy(SEM)(analysis) of the fracture section of PP/BaTiO_3 composites revealed that the fine ceramic particles were well dispersed in polymer matrix without assistance of any surfactant.The incorporation of BaTiO_3 greatly enhanced the dielectric constant of polypropylene.SEM of powdery specimens indicated that the strong shear and compression forces as well as friction that the pan mill exerted can(effectively) pulverize viscoelastic matters and result in microns level,or even nanosize particles.These actions also induced significant structure changes in the polymer phase during milling process,(resulting) in considerable intimacy as well as strong interaction between the polymer and inorganics,which was also confirmed by TGA and FT-IR analysis.So S~3M is a promising strategy for design of highly dispersed nanocomposites,especially for these systems with high inorganic filling.