基于废弃丝瓜络的杂化导电网络的协同导电机理研究

Currently, a large number of processing waste of loofah sponge (LS) commodity has not been effectively used in China. On the other side, multiple conductive fillers are used to modify the polymer based composites, which can reduce the amount of conductive fillers (especially precious metals) and improve the conductive properties of the composites, which has important application value. However, it is difficult for the simple blending approach to obtain the well-ordered assembly structure of LS fibers, conductive fillers, and polymer, and the basic scientific issues such as the synergistic enhanced conductive mechanism are not clear. Moreover, random lapping of conductive fillers leads to high contact resistance. In this proposal, based on effective utilization of LS waste, we applied in-situ assembly method to directly fabricate hybrid conductive network structure by grafting conductive fillers into the cellular micro channels inside the LS fibers. Synergistic conductive ability of the hybrid conductive network was enhanced by design and control of arrangement of conjugated π bond and metallic bond in micro channels. Based on that, polymer based electrical conductive nano-composites were in-situ fabricated. The synergistic enhanced conductive mechanism will be clarified by establishment of crystallization model, rheological model and conductive model, which will provide the theoretical support for comprehensive utilization of LS waste and the development of electromagnetic shielding materials, flexible sensors and wearable equipment.

目前我国大量的丝瓜络加工废弃物未得到有效利用。采用多种导电填料对聚合物基复合材料进行改性，在降低导电填料（特别是贵金属）用量的同时提升材料的导电性能，具有重要应用价值。传统的改性方法是将多种导电填料简单共混，不能控制材料的微结构；同时杂化导电网络中的填料之间大都是无规搭接，具有较高的接触电阻。此外，杂化导电网络的协同导电机理等基础科学问题尚不清楚。本项目基于废弃丝瓜络的高效利用，在丝瓜络纤维内部的蜂窝状微米孔道表面接枝石墨烯、纳米银、聚吡咯等多种纳米导电填料作为杂化导电网络，通过设计导电化学键在微米孔道中的排列方式以降低填料间的能量势垒，实现导电填料在微米孔道中的有序组装。在此基础上原位构筑聚合物基导电纳米复合材料，系统分析纤维的微米孔道及其杂化导电网络对复合材料结晶结构、流变行为和导电性能的影响，揭示复合材料的协同导电机理，为电磁屏蔽材料、柔性传感器和可穿戴设备等领域的发展提供支撑。

丝瓜络是成熟丝瓜干燥后的维管束，其主要成分为纤维素，由多层纵横交错的纤维形成三维网络结构。目前我国大量的丝瓜络加工废弃物未得到有效利用。利用废弃丝瓜络的结构特性制备高性能、高附加值的复合材料，具有优良的生态和经济效益，对解决环境和资源紧缺问题具有一定帮助。经过三年的系统探索，我们取得的主要亮点包括：（1）建立了杂化导电网络的合成方法，解析了纳米导电填料的种类、数量和位置对杂化导电网络空间结构的影响规律，获得了一种共轭π健-金属键-离子键有序调控的普适性策略；（2）利用杂化导电网络上的活化位点，将聚合物分子原位引入到导电网络中，获得了形态可控的聚合物基导电纳米复合材料通用制备方法，揭示了杂化导电网络性质和构筑工艺对复合材料形态调控的影响机制；（3）明确了杂化导电网络设计合成-制备条件-形态调控三者之间的关系，阐明了微米孔道及其杂化导电网络对复合材料结晶结构、流变行为和导电性能的独特作用。最后，探索了微米孔道的电化学传感性能。为废弃丝瓜络的高值化综合利用和丝瓜络基导电复合材料的发展提供了一定的理论和技术支撑。共发表论文32篇，其中SCI收录29篇；申请国家发明专利14件，参加学术会议2次，入选江苏省“青蓝工程”优秀骨干教师，获常州市自然科学优秀科技论文三等奖。