聚吡咯包覆二氧化钛纳米自修复微胶囊制备及其形成机制

目的以聚吡咯为有机囊壁、纳米二氧化钛为无机囊芯制备粒径均一的纳米级自修复微胶,并探讨其形成机制。方法采用化学氧化法于超声环境中制备出有机/无机复合自修复微胶囊,利用SEM、FT-IR和XRD等方法,研究了不同制备工艺对微胶囊粒径、形貌、结构的影响。结果阴离子型表面活性剂更有利于聚吡咯在二氧化钛颗粒表面包覆,在十二烷基苯磺酸钠(SDBS)和超声波作用下,吡咯单体以纳米二氧化钛为核心聚合,形成具有纳米晶结构的聚吡咯囊壁,进而获得粒径均一、直径约为100 nm的球形PPy-TiO_2复合纳米微胶囊。结论由于阴离子表面活性剂在二氧化钛粉体表面的化学吸附,形成了有机修饰层,从而可在有效抑制纳米二氧化钛自身团聚的同时,促进吡咯单体在其表面的包覆聚合。

Preparation and Formation Mechanism of Polypyrrole-coated TiO2 Nano Self-healing Microcapsules

The work aims to prepare uniform-size nanoscale self-healing microcapsules with polypyrrole as organic capsule wall and TiO2 as the inorganic capsule core and discuss its formation mechanism. Organic/inorganic composite self-healing microcapsules were synthe-sized by chemical oxidation polymerization under an ultrasonic condition. Effects of different preparation technologies on grain size, morphology and structure were studied by means of SEM, XRD and FT-IR. The results indi cated that the anionic surfactant was more beneficial to the surface coating of polypyrrole on TiO2 particles. Under the effects of sodium dodecyl benzene sulfonate (SDBS) and ultrasonic wave, the polypyrrole monomer aggregated with TiO2 as the core and formed polypyrrole capsule wall to obtain a spherical PPy-TiO2 composite namo microcapsule of uniform grain size and diameter of about 100 nm. A modified layer is formed due to chemisorptions of the anionic surfactant on TiO2 powder surface, which can inhibit spontaneous agglomeration of TiO2 and promote coating and agglomeration of polypyrrole monomer on its surface.