固相法制备聚噻吩/聚吡咯/二氧化钛膜及电化学腐蚀性能

在水蒸气气氛下,制备出表面富含羟基的纳米Ti O_2颗粒,然后在室温和氧化剂三氯化铁存在下,通过化学固相氧化法,在不锈钢表面制备出聚噻吩/聚吡咯/Ti O2(PTH/PPy/TiO_2)薄膜。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、热重分析(TG)、电化学阻抗(EIS)等技术手段对产物的微观形貌、热稳定性和耐腐蚀性能进行了研究,并讨论了不同纳米TiO_2含量对复合材料的结构和性能的影响。结果表明,在其使用温度(20~300℃)下,PTH/PPy/6%Ti O_2(质量分数)膜热分解温度为450℃,能够满足其使用要求。用PTH/PPy/TiO_2膜保护的不锈钢比裸露的不锈钢的自腐蚀电位高出0.8 V以上,而腐蚀电流密度降低了2个数量级。TiO_2的添加明显的提高了PTH/PPy材料的抑制腐蚀的能力,并且由于TiO_2的加入能够使聚合物与无机纳米粒子之间能够紧密地结合在一起,减少膜的缺陷,增大复合材料与金属基体的力学性能,使得膜结构更加的致密,从而减缓不锈钢的腐蚀。

Preparation of Polythiophene/Polypyrrole/TiO2 Composite Conductive Polymers by Solid-state Method and Its Anti-corrosion Properties for Stainless Steel

Polythiophene(PTH)/Polypyrrole(PPY)/TiO₂ conductive polymer composites materials were prepared by chemical solid-phase oxidation reaction in the presence of TiO₂ nanoparticles and ferric chloride at room temperature. X-ray crystallography(XRD), scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FT-IR), thermogravimetric analysis(TG) and electrochemical impedance spectroscopy(EIS) were employed to characterize the morphology, thermal stability and anti-corrosion properties of the composites with different dopping amounts of nano-TiO₂. PTH/PPy/6%TiO₂ conductive polymer film at the application temperature(20~300 ℃) meets the anti-corrosion requirements to prevent the stainless steel corrosion with a 0.8 V potential higher than the free corrosion potential of bare stainless steel, while the corrosion current densities are lower two orders of magnitude. Nano-TiO₂ improves the anode protection and the anti-corrosion properties of the PTH/PPY material. Furthermore, nano-TiO₂ bends the polymer tightly to increase the mechanical properties of the composites by reducing membrane defects.