Department of Chemical Engineering, National Tsing-Hua University, Hsin-Chu 30013, Taiwan, ROC.
ACS Appl Mater Interfaces. 2013 Feb;5(3):869-77. doi: 10.1021/am302494c. Epub 2013 Jan 15.
This study fabricates amine (NH(2))-functionalized graphene oxide (GO)/polyimide(PI) composite films with high performance using in situ polymerization. Linear poly(oxyalkylene)amines with two different molecular weights 400 and 2000 (D400 and D2000) have been grafted onto the GO surfaces, forming two types of NH(2)-functionalized GO (D400-GO/D2000-GO). NH(2)-functionalized GO, especially D400-GO, demonstrated better reinforcing efficiency in mechanical and thermal properties. The observed property enhancement are due to large aspect ratio of GO sheets, the uniform dispersion of the GO within the PI matrix, and strong interfacial adhesion due to the chemical bonding between GO and the polymeric matrix. The Young's modulus of the composite films with 0.3 wt % D400-GO loading is 7.4 times greater than that of neat PI, and tensile strength is 240% higher than that of neat PI. Compared to neat PI, 0.3 wt % D400-GO/PI film exhibits approximately 23.96 °C increase in glass transition temperature (T(g)). The coefficient of thermal expansion below T(g) is significantly decreased from 102.6 μm/°C (neat PI) to 53.81 μm/°C (decreasing 48%) for the D400-GO/PI composites with low D400-GO content (0.1 wt %). This work not only provides a method to develop the GO-based polyimide composites with superior performances but also conceptually provides a chance to modulate the interfacial interaction between GO and the polymer through designing the chain length of grafting molecules on NH(2)-functionalized GO.
本研究采用原位聚合的方法制备了具有高性能的胺（NH(2)）功能化氧化石墨烯（GO）/聚酰亚胺（PI）复合膜。两种不同分子量的线性聚（氧化亚烷基）胺 400 和 2000（D400 和 D2000）已接枝到 GO 表面，形成两种类型的 NH(2)-功能化 GO（D400-GO/D2000-GO）。NH(2)-功能化 GO，特别是 D400-GO，在机械和热性能方面表现出更好的增强效率。观察到的性能增强归因于 GO 片的大纵横比、GO 在 PI 基体中的均匀分散以及 GO 与聚合物基体之间的化学键合所导致的强界面附着力。含 0.3wt%D400-GO 负载的复合膜的杨氏模量比纯 PI 高 7.4 倍，拉伸强度比纯 PI 高 240%。与纯 PI 相比，0.3wt%D400-GO/PI 薄膜的玻璃化转变温度（T(g)）提高了约 23.96°C。在 T(g)以下，D400-GO/PI 复合材料的热膨胀系数从纯 PI 的 102.6μm/°C（102.6μm/°C）显著降低至 53.81μm/°C（降低 48%），对于低 D400-GO 含量（0.1wt%）的 D400-GO/PI 复合材料。这项工作不仅提供了一种开发具有优异性能的基于 GO 的聚酰亚胺复合材料的方法，而且通过设计接枝在 NH(2)-功能化 GO 上的分子的链长，从概念上为调节 GO 和聚合物之间的界面相互作用提供了机会。
