【作者】 刘丹；

【导师】 陈守刚；

【作者基本信息】 中国海洋大学 ， 材料物理与化学， 2015， 硕士

【摘要】 环境友好型防污剂在解决海洋生物污损方面起到日趋重要的作用。壳聚糖(CS)具备优秀的生物相容性、抑菌性。碳纳米管的结构与聚合物近似,将碳纳米管与壳聚糖复合,不仅能利用生物大分子的亲水性来改善碳纳米管的分散性,更可能实现不同材料性能的互补或协同作用,为其在防污领域的广泛应用提供条件。本论文以碳纳米管、壳聚糖为基本研究材料,以多巴胺为桥梁材料,进行纳米复合材料的制备,并通过电化学测试技术、抑菌及抑制硅藻实验分别对复合材料的缓蚀及防污性能进行了表征。主要工作如下：(1)利用多巴胺在不同pH值条件下(碱性、酸性)的不同反应方式对碳纳米管进行温和的包覆改性。通过实验证实了改性效果,两种改性方法均有效改善了碳纳米管的分散性,其中经多巴胺单分子层(micaDA)修饰后的多壁碳纳米管(MWCNTs)表面存在大量氨基集团,在水溶液中的分散性和稳定性更高；聚多巴胺包覆的碳纳米管(PDA-MWCNTs)复合材料中碳纳米管管壁外均匀包覆了厚度约为4 nm的PDA层,而micaDA-MWCNTs上多巴胺单层膜膜厚较薄,整体热失重率远低于PDA-MWCNTs。(2)结合壳聚糖的螯合作用引入纳米银粒子,以聚多巴胺包覆的碳纳米管作为模板,CS作为保护剂和稳定剂,通过液相还原法制备得到聚多巴胺包覆碳纳米管/纳米银/壳聚糖复合材料(CS/PDA-MWCNTs/Ag)复合溶胶,改变反应条件得到最佳制备工艺条件。复合溶胶中PDA-MWCNTs的管壁及溶胶中均匀分散着AgNPs颗粒；纳米银与CS及PDA-MWCNTs复合,改善了CS的热稳定性。抑菌试验表明,复合溶胶对大肠杆菌、金黄色葡萄球菌及鳗弧菌的最低抑菌浓度分别为4 μg/mL、5 μg/mL及5.5μg/mL,表现出优异的抑菌性能及广谱抑菌性能。电化学阻抗谱与极化测试表明复合溶胶是一种混合型缓蚀剂,对腐蚀难度和腐蚀速率的性能都有较好的提升,复合溶胶中的几种材料的协同效应,在基体表面形成多元保护膜,增强了材料的缓蚀性能。(3)通过控制溶液的pH值,在酸性条件下制备了单层多巴胺改性的多壁碳纳米管,然后以戊二醛作为反应中间桥梁,共价接枝制备得到碳纳米管/多巴胺/壳聚糖复合材料。TEM照片表明,CS/micaDA-MWCNTs复合材料的管壁外面和管端都被约为6 nm厚的膜层均匀包覆起来。采用多巴胺单层膜包覆碳纳米管,达到了不破坏碳纳米管结构同时又增加碳纳米管表面活性基团数量的目的,从而增加了复合材料中壳聚糖的接枝量,TGA分析表明,壳聚糖的接枝量约为71.78%,复合材料的热性能得到提升。抑制硅藻生长实验表明,由于碳纳米管的缓释及抑制硅藻生长作用,复合材料对两种常见海洋硅藻——小舟形藻和成排舟形藻表现出长效抑制性能。抑菌试验表明复合材料对革兰氏阳性菌(金黄色葡萄球菌)、革兰氏阴性菌(大肠杆菌)及海洋菌(鳗弧菌)都表现出一定抑菌性能,具有广谱抑菌性。更多还原

【Abstract】 Nowadays, environment-friendly antifouling agent plays an increasingly important role in marine biofouling. Chitosan (CS) is a biocompatible, non-toxic biopolymer as a carbohydrate polymer. The structure of carbon nanotubes is similar to chitosan. The compound not only can improve the dispersibility of carbon nanotubes by utilizing hydrophilic biological macromolecules, and more likely to achieve complementary or synergistic effects, which would be widely used in the field of antifouling.In this paper, multi-wall carbon nanotubes (MWCNTs) and CS were chosed as matrix materials, dopamine (DA) as a bridge material for preparing nanocomposites, and investigate the anti-corrosion and anti-biofilm properties by electrochemical testing technology, bacteriostatic experiments and diatom inhibition experiments. The major contents can be summarized as follows:(1) The prepare method of moderate-modified MWCNTs was utilizing by self-polymerization of dopamine under different pH conditions reaction mode. Both approaches were effective to improve the dispersibility of MWCNTs, micaDA-coated carbon nanotubes has useful functional groups such as amino groups, so it can provide a significant increase in dispersion and stability. The TEM results indicate that carbon nanotubes were wrapped with 4 nm of polydopamine (PDA) layer, while the film thickness of single-layer dopamine film-coated carbon nanotubes (micaDA-MWCNTs) is thin. In this instance, the weight loss of micaDA-MWCNTs is far below than that of PDA-MWCNTs.(2) Using the pre-synthesis PDA layer as a nanoscale guide to form uniform Ag nanoparticles (AgNPs) on the surface of PDA/MWCNTs. In this system, CS plays a role of protective agent and stabilizer. CS/PDA-MWCNTs/Ag composite sol was prepared by liquid-phase reduction. Transmission electron microscopy (TEM) photos showed AgNPs distributed adequately in the wall of PDA/MWCNTs and the composite sol. Composition of CS and PDA-MWCNTs composite improved thermal stability of CS. According to the results of antibacterial tests, the minimum bactericidal concentration of composite sol against E. coli, S. aureus and Vibrio anguillarum is 4 μg/mL,5 μg/mL and 5.5 μg/mL, respectively. Electrochemical impedance spectroscopy and polarization tests showed CS/PDA-MWCNTs/Ag composite sol is a mixed-type inhibitor. Synergies of several materials form a multi-substrate surface protective film on substrate, which substantially enhanced the corrosion performance of materials.(3) By controlling the pH of the solution, micaDA/MWCNTs were prepared under acid condition. CS/micaDA/MWCNTs composites were prepared by covalent grafting method with glutaraldehyde as a bridge material between chitosan and multi-walled carbon nanotubes (MWCNTs). TEM photographs show that about 6 nm membrane layer of Chitosan is well-distributed coated on the surface of micaDA-MWCNTs. The effective biocompatible strategy of dopamine monolayer film coated carbon nanotubes not only can achieve the object of modified without breaking the carbon nanotube structure, and more likely to increase significant amounts of surface active groups of MWCNTs, thereby increasing the content of grafted chitosan. Thermogravimetry analysis (TGA) data showed chitosan graft was approximately 71.78%. Diatom growth inhibition experiments indicated that due to the sustained-release effect and the diatom inhibition of carbon nanotubes, CS/micaDA-MWCNTs composites showed long-lasting inhibition performance against Navicula parva and Navicula rows.Antibacterial tests showed that CS/micaDA-MWCNTs can obtain good antibacterial property against E. coli, S. aureus and Vibrio anguillarum.更多还原