- 學位論文
室溫硬化型仿生疏水環氧樹脂/石墨烯複合材料及圓盤型液晶材料之合成及其防腐蝕性質之研究
Preparation and Anticorrosion Studies of R.T. Curable Biomimetic Epoxy/Graphene Composites and Discotic Crystal Materials
摘要
本論文利用室溫硬化方式成功製備出添加不同含碳氧官能基比例石墨烯之環氧樹脂奈米複合材料，並另外探討其仿生結構的疏水性；另外，發展出新型的防蝕塗料，將圓盤型液晶的結晶等特性運用在防蝕方面。本研究內容共分為三個部分： 第一部分由添加不同碳氧官能基含量之石墨烯，形成的環氧樹脂/石墨烯奈米複合材料 (EGN)，透過傅利葉轉換紅外線光譜儀(FT-IR)、穿透式電子顯微鏡(TEM)分別作結構鑑定與觀察分散情形；並透過循環伏特電位儀(CV)、交流阻抗模組(Impedance)測定，了解複合材料對於金屬表面的防蝕特性，防蝕效果提升之主要原因為：不同含碳氧官能基含量的石墨烯添加到環氧樹脂後，會有著不同的分散性差異，相較於純的環氧樹脂來說，皆會延長氣體在薄膜中的滲透路徑。此外，利用氣體透過率分析儀(GPA)也可得知阻氣效果提升，進而得到防蝕的效益。另外，好的分散性也能使材料本身機械性質、熱穩定性、熱導有明顯地提升。 第二部分透過模板複製千年芋上的奈米微結構，並製備出仿生超疏水表面之環氧樹脂/石墨烯奈米複合材料(HEGN)，對於表面結構使用掃描式電子顯微鏡(SEM)進行觀察。由接觸角測試中可發現，其接觸角由一開始沒結構之純環氧樹脂約82度，最高可提升至有結構的127度；並藉由防腐蝕測定可得知材料在添加石墨烯，以及在表面複製上仿生結構後，有更明顯的防腐蝕效果，其原因總結可歸納為三點：一、環氧樹脂本身就是一個好的物理屏障；二、具有仿生結構的表面，造成疏水的排斥性，進一步可降低環氧樹脂表面與水及腐蝕性介質的接觸；三、良好分散性的石墨烯，能延長氣體在薄膜中的滲透路徑，進而達到防蝕的效果。 第三部分則是將液晶當作防蝕塗層作為探討，除了鑑定外，為了解其加熱前後結晶性的差異，透過偏光圖、XRD、SEM等去對材料本身加以探討；並透過防蝕測試，從接觸角可以看出液晶的疏水性，再藉由電化學防蝕測試，將液晶材料(六苯并寇)經由加熱前後的差異在不同環境下(酸鹼鹽溶液)，及不同時間(30分、7天)作為依據，探討其防蝕上的差異。
並列摘要
Epoxy is a candidate material that is showing promise for use in a wide range of applications in several advanced technologies. In this research, Bisphenol A diglycidyl ether (BADGE) with B210 and graphene nanosheets, were prepared by Room-temperature cured. This study as this epoxy nancomposites is divided into two parts: In the first part, the different carboxylic group content for functionalized graphene nanosheets were incorporated into the epoxy a three-roll mill at room temperature, leading the formation of epoxy/grapheme nancomposites (EGN) and then characterized by Fourier-Transformation infrared (FTIR) spectroscopy and transmission electron microscopy (TEM).The epoxy nancomposites could be used as advanced coatings that protect metals against corrosion. Enhancement of corrosion protection of EGN coatings on CRS electrode could be interpreted by the main reasons: The different-dispersed graphene nanosheets embedded in epoxy matrix could act as hinder with the different carboxylic group content for functionalized graphene nanosheets than pure epoxy, which to further effectively enhance the oxygen barrier property of EGN, as evidenced by gas permeability analyzer (GPA).The better dispersion capability of carboxyl-graphene with higher carboxylic group contents in EGN membranes was found to lead significant enhanced mechanical strength, thermal stability and thermal conductivity on the measurements of dynamic mechanical analysis (DMA), tensile test, thermo-gravimetric analysis (TGA) and TPS technique. The second part, nanocasting technique was used to obtain a biomimetic hydrophobic epoxy/grapgene nancomposite(HEGN) surface structure from a natural Xanthosoma sagittifolium leaf. The morphology of the surface of the as-synthesized HEGN coating was investigated using scanning electron microscopy (SEM). The contact angle of water droplets on a sample surface can be increased from ~82° (epoxy surface) to ~127° (hydrophobic epoxy and EGN). It should be noted that EGN coating was found to provide an excellent corrosion protectioneffect on cold-rolled steel (CRS) electrode. Enhancement of corrosion protectionusing EGC coatings could be attributed to the following three reasons: (1) epoxy could actas a physical barrier coating, (2) the hydrophobicity repelled the moisture and furtherreduced the water/corrosive media adsorption on the epoxy surface, preventing the underlyingmetals from corrosion attack, and (3) the well-dispersed graphene nanosheets (GNSs)embedded in HEGN matrix could prevent corrosion owing to a relatively higher aspect ratiothan clay platelets, which enhances the oxygen barrier property of HEGN. The third part, Columnar liquid crystal (HBC-C12) was successfully applied for Corrosion resistance of iron. The LC-coating on Fe surface not only exhibited corrosion resistance property but also show the suitability of critical environment, which is attributed to excellent hydrophobic and self-assembled ability of liquid crystal.