纳米银线-石墨烯改性环氧树脂胶黏剂的导电性能和导热性能的研究

In electrically conductive adhesives (ECAs), especially isotropically conductive adhesives (ICAs), the use of epoxies has been ''the state-of-the-art'' for a long time. Epoxies have many beneficial properties and the desirable properties may further be improved with a suitable choice of solvents, fillers, colorants, flame retardants, flexibilizers and cure accelerators. A novel epoxy adhesive with high electrical and thermal properties is significant for the microelectronic packaging technology, especially, the LED packaging technology. To improve the adhesives' electrical and thermal conductivity, the amount of conducting filler particles has to be increased normally. However, a new epoxy adhesive will be prepared with low filler contents. The silver nanowires and graphene have been chose and will be synthesized and filled into the epoxy adhesive. The formula of the epoxy composite, processing parameters, morphologies of silver nanowires and graphene and ratios of the two fillers will be changed to form a three-dimensional -network topological structure in the epoxy matrix. The network topological structure containing electrical and thermal conductive paths has been combined by one-dimensional fibers of silver nanowires and two-dimensional plates of grapheme. It is a new method to obtain the epoxy adhesive with high electrical and thermal conductivities. Besides, the viscoelastic behaviors of the flow including different fillers, curing agent and other additives in epoxy matrix will be studied to determine a reliable technological route for stable preparation of products. Enrich and develop the theoretical dynamics models of electron motion in the combining network of long route paths and short route paths. The thermal conducting property and thermal conducting mechanism of the complex network in epoxy adhesives during and after the curing process will also be investigated. Our studies will provide a basis for the development of new modified epoxy adhesive.

环氧树脂胶黏剂是一种很有潜力的导电胶，具有广阔的市场前景，而具有高导热性能的环氧树脂胶黏剂对微电子封装技术尤其是LED封装技术的发展和实际应用具有重要意义。本项目拟研制一种结合纳米银线优异导电性能和石墨烯导热性能的改性环氧树脂胶黏剂，通过形态调控纳米银线和石墨烯在环氧树脂基体中的分散程度、配方组成和加工工艺，使二者搭接形成纤维和片层交织的三维拓扑网络结构，达到控制纳米导电-导热网络的目的，为制备高导热、高导电的网络状拓扑结构的环氧树脂填充体系提供新的途径；研究复配填充体系混合流体的粘弹特性，为新型胶黏剂的开发研制确定一条工艺成熟、性能稳定的制备路线；丰富和发展一维-二维复杂网络中电子运动的动力学及场隧道效应发射理论模型，同时提出复杂网络在环氧树脂固化过程中和固化后的导热机理，为新型改性环氧树脂胶黏剂的开发奠定基础。

高品质的金属纳米结构和原始石墨烯的组合在许多应用领域有很好的前景，采用简单的方法大规模制备金属纳米粒子/纯石墨烯杂化材料，该方法同时具有PAMAM树枝体修饰的无缺陷石墨烯和金属纳米粒子均相粘附在石墨烯表面及非共价键功能化两种过程；金属纳米粒子均匀附着用聚酰胺 - 胺（PAMAM）树枝状优化的非共价键功能化的无缺陷的纯净石墨烯表面上。形成了无溶剂的稳定的PAMAM功能化纳米石墨烯液体，其混合的石墨烯片保持固有的结构和均匀分散。银NP（AgNP）杂化石墨烯的混合与均匀的分散是通过使用PAMAM作为热还原法中的稳定剂和还原剂，AGNPS的低温烧结用，作为纳米级填料的低逾渗阈值的高品质的原始石墨烯的优良的导电性的组合效应，提高了环氧基导电复合材料的电互联，这种方法可能导致大规模生产用于广泛应用范围基于石墨烯的复合材料。. 用所4-氨基苯甲酸通过Friedel–Crafts acylation反应制备功能化的石墨烯。石墨的边缘被高度的剥离，功能化的主要区域是在石墨的边缘，石墨的内部结构保持完整。通过超声波在低沸点溶剂中轻易可以把石墨剥离成石墨烯片层。功能化的石墨烯片层用作环氧导电胶的增强材料。结果表明添加0.6wt%的石墨烯片层可以是导电性增加31.3%。剪切强度从8.7MPa增加到15.2MPa.环氧基体通过共价键与石墨烯相连，形成三维网络结构。石墨烯与银片之间形成桥梁可以有效的增强导电性能。. 研究了四种固化方式的溶剂和无溶剂导电胶的性能，用于多芯片模块。用DSC和TGA研究了溶剂和无溶剂导电胶的固化和热降解行为。即使在相同的温度和时间，四种固化方式导电胶的体积电阻率也明显不同。溶剂和无溶剂导电胶的导电趋势也是明显不同。溶剂导电胶的较好和较差的导电性能分别在室温固化和保持温度固化。然后，无溶剂导电胶是恰恰相反。所有导电胶的热膨胀系数在焊料回流工艺后都倾向降低。用TMA，TGA和三维变形仪和扫描电子显微镜等探索了原因。.通过采用三乙醇胺与硝酸银结合生成配位反应生产Ag+络合物，并作为环氧树脂固话促进剂，在环氧树脂固化温度下，络合物原位热分解成三乙醇胺化合物和纳米银，三乙醇胺化合物参与环氧树脂的固话过程，使体系的粘度增大，防止了纳米银粒子的团聚，小颗粒的纳米银在镀银铜粉表面及界面发生了熔融烧结，一方面构建了纳米银烧结的导电网络，增强了导电通路，一方