具可調機械強度之彈性氣凝膠及具側鏈苯胺五聚體之電活性環氧樹脂/還原性氧化石墨烯複合防蝕塗料之合成、鑑定與應用研究

Synthesis, Characterization and Application of Flexible Aerogel with Tunable Mechanical Strength and Electroactive Epoxy/rGO Composite Anticorrosion Coating

翁誌偉(Chih-Wei Weng)

指導教授 ： 葉瑞銘

中原大學/理學院/化學研究所/碩士(2018年)

https://doi.org/10.6840/cycu201800613

摘要

本篇碩士論文內容主要分為兩個部分，第一部分為電活性環氧樹脂的製備、鑑定及防蝕性能探討; 第二部分則是機械強度可調之彈性矽化物氣凝膠之合成、鑑定與物性探討。
第一部分的研究以電化學法探討具有電活性環氧樹脂/石墨烯複合塗料在冷軋鋼的防腐蝕應用上。 首先，使用氧化偶合法製備側鏈電活性-二胺單體，並利用傅利葉轉換紅外光譜儀、液相層析質譜儀及核磁共振儀進行電活性單體結構鑑定。 此外，使用紫外-可見光光譜儀及循環伏安儀確認其氧化還原特性。
將電活性二胺單體與環氧樹脂前驅物進行開環熱聚合反應來合成電活性環氧樹脂塗料，並同時合成電活性環氧樹脂塗料加入1 wt-% 石墨烯來合成電活性複合塗料。 藉由一系列電化學量測方式及氣體穿透分析可知，電活性複合塗料對冷軋鋼具有最好的防腐蝕能力。 其原因可分為兩部分： (1) 藉由加入還原氧化石墨烯提升防蝕塗料之電催化效果，使鈍性金屬氧化層(Fe2O3及Fe3O4)快速升成。 (2) 電活性環氧樹脂內的苯胺五聚體與還原氧化石墨烯之間形成分子間作用力增加還原氧化石墨烯在高分子內的分散能力，有效提升塗層氣體(特別是氧氣)的阻隔特性。
接下來，第二部分是機械強度可調之彈性矽化物氣凝膠之研究，首先以乙烯基三甲氧基矽烷與2,2'-（亞乙二氧基）二乙硫醇經紫外光照射合成所需之前驅物，並以溶膠-凝膠法製備出未改質與利用甲基三甲氧基矽烷進行改質之彈性氣凝膠。 合成出之前驅物以傅利葉轉換紅外光譜與核磁共振儀鑑定其結構，再將合成之彈性氣凝膠藉由固態核磁共振儀確認其化學結構。 合成出之彈性氣凝膠，利用掃描式電子顯微鏡與比表面積及孔隙度分析儀 (BET) 來進行彈性氣凝膠的孔洞性質鑑定，得知經改質後之彈性氣凝膠孔洞分佈密度較高，且具有較高的比表面積及較多的孔隙率。 彈性氣凝膠亦進行接觸角測試，得到隨著甲基三甲氧基矽烷增加，其疏水特性也逐漸提升。 同時，彈性氣凝膠對熱傳導係數進行應用上之分析，由分析結果獲得當甲基三甲氧基矽烷比例提升時，其熱傳導係數亦會提升。
此外，利用硬度計與動態機械熱分析儀進行彈性氣凝膠之機械強度測試，當甲基三甲氧基矽烷添加量為0 wt%、1 wt% 與10 wt% 時，由硬度計測得的值則為27、35與67逐漸提升。接著，動態機械熱分析獲得的數值為壓縮量11.44 %、10.89 % 與 7.65 % 逐漸降低。最後，從上述結果得知: 改質後之彈性氣凝膠可藉由甲基三甲氧基矽烷添加的多寡對其結構之機械強度進行調整。

關鍵字

苯胺寡聚體 ； 環氧樹脂 ； 側鏈電活性 ； 防腐蝕 ； 還原氧化石墨烯 ； 彈性氣凝膠 ； 機械強度

並列摘要

This thesis is mainly divided into two parts. The first part discusses the preparation, characterization and anticorrosion application of electroactive epoxy resin/reduced graphene oxide (rGO). The second part discusses the preparation and characterization and physical property studies of flexible aerogels with tunable mechanical strength.
In the part 1, first of all, side-chain electroactive diamine monomer (DAAP) was synthesized by oxidative coupling reactions, followed by characterized through Fourier transform infrared (FT-IR) spectroscopy, liquid chromatography mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy. Moreover, the redox capability of as-prepared monomer was investigated by UV-vis spectroscopy and cyclic voltammetry (CV).
An electroactive epoxy resin coating was prepared by reacting as-synthesized electroactive monomer and epoxy pre-polymer through performing the thermal epoxide-ring polymerization reactions. The corresponding composite containing 1 wt% of rGO was also prepared for comparative studies. Subsequently, the corrosion protection of as-prepared all coating materials upon cold rolled steel (CRS) electrode was evaluated by a series of electrochemical corrosion measurements in saline condition. It should be noted that CRS coated with composite containing 1 wt% of rGO was found to exhibit best anticorrosion performance based on the studies of Tafel plots and impedance spectroscopy. Gas permeability analysis (GPA) of all as-prepared membranes showed that the composite containing 1 wt% of rGO coating exhibited the best oxygen gas barrier property. The possible reason for the enhancement of composite coating in anticorrosion as compared to that of neat epoxy resin can be drawn into two conclusions: (1) incorporation of 1 wt-% of rGO into electroactive epoxy may enhance the electro-catalytic effect of electroactive epoxy to promote the formation of densely passive oxide layer (Fe2O3 and Fe3O4). (2) The formation of π-π interaction between the aniline pentamer of electroactive epoxy coating and rGO led to the better dispersion capability of rGO in polymer coating matrix, implied the higher oxygen gas barrier property of composite coating as compared to that of neat polymer coating.
In the part 2, the research target focused on the preparation and characterization and physical property studies of flexible aerogels with tunable mechanical strength. First, the synthesis of precursor began with a click reaction of vinyltrimethoxynonane (VTMS) and 2,2'- (ethylenedioxy) diethanethiol (EDDET). Subsequently, the acid-catalyzed and base-catalyzed sol-gel reactions were used to turn precursor into generally flexible aerogel. Subsequently, MTMS was used as modifier to fine-tune the mechanical strength of flexible aerogels. The precursor was identified by FT-IR and NMR spectroscopy, and the chemical structures of synthesized flexible aerogel were confirmed by 13C- and 29Si- solid-state nuclear magnetic resonance spectroscopy (SSNMR).
The porous structure and surface area of synthetic flexible aerogels were identified by nitrogen adsorption – desorption. Surface morphological image and surface wettability of as-prepared flexible aerogels was observed by scanning electron microscope (SEM) and contact angle, respectively. Thermal conductivity measurement of as-prepared flexible aerogel was determined by Hot Disk TechMax H5DR with sensor design No. 5501.
It should be noted that, as the MTMS increased, the flexible aerogel have higher specific surface area and porosity. Moreover, increase of hydrophobic properties and thermal conductivity was also accompanied with the increase of MTMS loading. In addition, the mechanical strength of the flexible aerogel was measured using a durometer and dynamic mechanical thermal analysis (DMA). When the loading of methyltrimethoxydecane was 0 wt%, 1 wt% and 10 wt%, the corresponding hardness agent was increased from 27 to 35 and 67. On the other hand, the compressibility values obtained by dynamic mechanical thermal analysis were gradually reduced from 11.44 % to 10.89 % and 7.65 %. From the analysis results, flexible aerogel was able to fine-tune the mechanical strength with the addition of MTMS.

並列關鍵字

Aniline oligomer ； Epoxy ； electroactive ； Anticorrosion ； Reduced graphene oxide ； Flexible aerogel ； Tunable mechanical strength

參考文獻

[1] Y. Wei, J. Xu, H. Dong, J. H. Dong, K. Y. Qiu, Chem. Mater., 1999, 11, 2023

[2] D. Chapman, R. J. Warm, A. G. Fitzgerald, A. D. Yoffe, J. Chem. Soc. Faraday Trans., 1964, 60, 294

[3] H. Shirakawa, S. Ikeda, Polymer., 1971, 2, 231

[4] (a) H. Shirakawa, E. J. Lousi, A. G. MacDiarmid, C. K. Chiang, A. J. Heeger, J. Chem. Soc, Chem. Commun., 1977, 578 ；(b) C. K. Chiang, C. R. Fincher, Y. W. Park, A. J. Heeger, H. Shirakawa, E. J. Lousi, S. C. Gau, A. G. MacDiarmid, Phys. Rev. Lett., 1977, 39, 1098

[5] A. J. Epstein, A. G. MacDiarmid, J. Chem. Soc. Faraday Trans., 1989, 5