- 學位論文
具側鏈苯胺五聚體之電活性聚脲在金屬防腐蝕之應用研究
Electroactive polyurea coating with pendant Aniline Pentamer for Anti-corrosion application
摘要
本碩士論文的研究主軸為製備並鑑定具側鏈之電活性聚脲，進一步將其應用在金屬防腐蝕塗料的研究上。首先，利用氧化偶合法製備出具有電活性苯胺五聚體 (Aniline Pentamer，AP)，利用有機反應合成出二胺單體之側鏈苯胺五聚體 (P-DAM)單體，並且利用核磁共振光譜儀(1H-NMR)、複立葉紅外光譜儀(FTIR)及質譜儀(MS)對所合成的AP及P-DAM進行化學結構鑑定。接著，將P-DAM與異氰酸酯 (N-3300)進行高分子聚合反應，以製備出電活性聚脲(EPU-5, EPU-10)，並利用FTIR光譜確認所合成的電活性聚脲之特徵官能基，證實高分子的合成反應已經完成。在高分子的電活性確認方面，所合成之電活性聚脲之電活性(電催化能力)可進一步由電化學(循環伏安儀)及化學(紫外光-可見光吸收光譜儀)進行監控。由研究數據顯示: 含側鏈苯胺五聚體越多含量的電活性聚脲，具有較佳的電催化特性。 在電化學金屬防腐蝕塗料的測試方面，量測所製備塗層的塔伏曲線(Tafel plot)、奈奎斯曲線(Nyquist plot)及伯德曲線(Bode plot)。由量測的結果顯示: 電活性聚脲之金屬抗腐蝕能力比非電活性聚脲效果還要來的好。其原因是由於電活性聚脲能在冷軋鋼表層形成鈍性金屬氧化層來保護下方的金屬基板。另外，含側鏈苯胺五聚體越多含量的電活性聚脲，具有較佳的金屬防腐特性。代表具有較佳的電催化特性的電活性聚脲具有較佳的金屬防腐特性。所產生的鈍性金屬氧化層(如:Fe2O3或Fe3O4)的生成可進一步由拉曼光譜(Raman spectroscopy)來確認化學組成。
並列摘要
In this dissertation, electroactive co-polyureas containing pendant aniline pentamer (AP) was prepared and applied in corrosion protection coating, followed by investigated by a series of electrochemical corrosion measurements in saline conditions. First of all, AP was synthesized by oxidative coupling reaction, P-DAM was further synthesized by using AP as reactant. The as-prepared AP and P-DAM was characterized by proton-nuclear magnetic resonance (1H-NMR) spectroscopy, Fourier-Transformation infrared (FTIR) spectroscopy and mass spectroscopy. Subsequently, electroactive co-polyureas (EPU-5 and EPU-10) were prepared by reacting isocyanate precursor (N-3300)/harder (T-403) with P-DAM and monitored by FTIR spectroscopy. Electroactivity of as-prepared electroactive co-polyurea coatings upon indium tin oxide (ITO) electrode was investigated by electrochemical cyclic voltammetry and in-situ monitoring of chemical oxidation by UV-visible absorption spectroscopy. Studies showed that electroactive co-polyurea coatings with higher loading of pendant AP on ITO electrode exhibited higher electroactivity as compared to that of electroactive co-polyurea coatings with lower loading of AP. For the corrosion protection of as-prepared electroactive co-polyurea coatings upon cold-rolled steel (CRS) electrode was investigated by a series of electrochemical corrosion measurements such as Tafel plot, Nyquist plot and Bode plot. Electroactive co-polyurea coatings with higher loading of pendant AP upon CRS electrode was found to reveal better corrosion protection as compared to that of electroactive co-polyurea coatings with lower loading of pendant AP. The better corrosion protection of electroactive co-polyurea coatings with higher loading of pendant AP may be attributed to the corresponding higher redox capability, inducing more densely passive metal oxide layers (e.g., Fe2O3 and Fe3O4) formed upon the surface of metallic substrate. Passive metal oxide layers formed on the metallic substrate can be further identified by the studies of Raman spectroscopy.