负载植酸钠的壳聚糖微球改性水性涂层制备及防腐蚀性能研究

目的将负载缓蚀剂植酸钠的多孔壳聚糖微球添加到水性聚丙烯酸涂层中,研究涂层改性后的防腐蚀性能。方法利用油包水(W/O)乳化固化法制备壳聚糖微球,通过扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)研究微球的形貌性征。利用负压-浸渍法将缓蚀剂植酸钠负载到壳聚糖微球中,并利用热重分析(TGA)研究缓蚀剂的负载率。将负载缓蚀剂的微球按照质量分数5%添加到水性涂层中,利用电化学阻抗谱(EIS)研究涂层改性后的防腐蚀性能。结果 SEM图像表明,壳聚糖微球成球性良好,粒径为20~30μm。FT-IR及XRD结果表明,交联剂香草醛通过希夫碱反应以及氢键作用对壳聚糖进行交联,使得壳聚糖微球固化,并且结晶度降低。TGA结果表明,缓蚀剂植酸钠的负载率为25.79%。EIS结果表明,经负载缓蚀剂的壳聚糖微球改性后的水性聚丙烯酸涂层电荷转移电阻增加。结论水性聚丙烯酸涂层中的多孔壳聚糖控制植酸钠的释放,提高了缓蚀剂的利用率,改性后的涂层防腐蚀性能得到了提高。

Preparation and Anti-corrosion Property of Water-based Coatings Modified with Chitosan Microspheres Loaded with Sodium Phytate

The work aims to study the corrosion resistance of the modified coating by adding the mesoporous chitosan mi-crospheres of sodium phytate (load corrosion inhibitor) to the water-based polyacrylate coating. The chitosan microspheres were prepared by W/O emulsion solidification method. The morphology of chitosan microspheres was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The sodium phytate (corrosion inhibitor) was loaded into chitosan microsperes by negative pressure impregnation and the load rate of corrosion in-hibitor was studied by thermogravimetric analysis (TGA). The microsperes of load corrosion inhibitor were added to the wa-ter-based coating with the mass ratio of 5% and the corrosion resistance was studied by electrochemical impedance spectroscopy (EIS). The SEM image showed that the chitosan microspheres were of good spheronization and the size was 20~30μm. The re-sults of FT-IR and XRD showed that the chitosan was crosslinked by vanillin (cross-linking agent) through Schiff base reaction and hydrogen bond interaction, thus leading to the solidification of chitosan microspheres and the low level of crystalline. The TGA results showed that the load rate of sodium phytate was about 25.79%; the EIS results showed that the charge transfer re-sistance of the water-based polyacrylate coating modified by the chitosan microsperes of load corrosion inhibitor had been in-creased. The mesoporous chitosan in the water-based polyacrylate coating controls the release of the sodium phytate, thus im-proving the utilization rate of corrosion inhibitor, and the corrosion resistance of the modified coating is improved.