Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China.
Soft Matter. 2017 May 14;13(18):3431-3439. doi: 10.1039/c7sm00346c. Epub 2017 Apr 25.
The electrical percolation threshold of carbon black (CB) in thermoplastic polyurethane (TPU) decreases by 46% with the incorporation of 20 wt% polyamide copolymer (COPA) through selective localization of CB particles at the interface of sea-island structured TPU/COPA blends. Composites with a composition of TPU/20 wt% COPA/9 wt% CB were prepared by four different mixing sequences and their morphologies were investigated by FESEM and TEM. The majority of CB particles were observed at the interface of sea-island structured blends irrespective of the compounding sequence used, although the percentage of CB particles at the interface is considerably less in the composite prepared by adding COPA to premixed TPU/CB. The driving force for the interfacial localization of most CB particles is the hydrogen bonding of CB with both TPU and COPA, which is confirmed by FTIR and DMA investigations. CB particles act like Janus particle-type compatibilizers with bonded TPU molecules toward the TPU phase and bonded COPA chains toward the COPA phase. Highly efficient conductive paths are formed through the CB-covered domains and a short inter-domain distance.
通过将 20wt%聚酰胺共聚物（COPA）掺入到热塑性聚氨酯（TPU）中，可以使炭黑（CB）的电渗滤阈值降低 46%，这是因为 CB 颗粒通过选择性地定位在海-岛结构的 TPU/COPA 共混物的界面处。通过四种不同的混合顺序制备了组成分别为 TPU/20wt%COPA/9wt%CB 的复合材料，并通过 FESEM 和 TEM 研究了它们的形态。无论使用哪种复合顺序，大多数 CB 颗粒都观察到在海-岛结构共混物的界面处，尽管在通过向预混合的 TPU/CB 添加 COPA 制备的复合材料中，界面处的 CB 颗粒的百分比要少得多。大多数 CB 颗粒在界面处定位的驱动力是 CB 与 TPU 和 COPA 的氢键相互作用，这通过 FTIR 和 DMA 研究得到了证实。CB 颗粒充当具有与 TPU 相键合的 TPU 分子的 Janus 颗粒型增容剂，以及与 COPA 相键合的 COPA 链。通过 CB 覆盖的畴和短的畴间距离形成了高效的导电路径。
