Dispersion, agglomeration, and network formation of multiwalled carbon nanotubes in polycarbonate melts
Dispersion, agglomeration, and network formation of multiwalled carbon nanotubes in polycarbonate melts
复制标题
DOI：
10.1016/j.polymer.2007.12.024
复制
发表时间：
2008-02-18
期刊：
影响因子：
4.6
通讯作者：
Lellinger, Dirk
中科院分区：
文献类型：
--
作者：
Pegel, Sven;Poetschke, Petra;Lellinger, Dirk
使用小型混料机通过熔融混合将三种不同的工业上可用的多壁碳纳米管（MWNT）材料直接掺入聚碳酸酯中。尽管纵横比相似，但电渗透行为不同。 TEM 研究揭示了纳米管分散性的显着差异，这可归因于原始 MWNT 材料的不同分散性。结果表明，研究MWNT水分散体的沉降行为是评估纳米管分散性的一种简单方法。采用母料稀释制备的含有0.875 wt% MWNT的聚碳酸酯样品，研究了熔融加工条件与MWNT分散和分布之间的关系。在熔融混合过程中，只有高剪切力才能提供合适的MWNT分散体，因为首先促进MWNT解缠结，其次防止二次附聚。在低剪切力下，可以观察到先前分散良好的 MWNT 发生团聚。在热压过程中，可以通过熔体温度和压制速度等加工条件来控制网络或 MWNT 排列以及由此产生的电导率。如介电谱所示，某种纳米管团聚体可以增强电渗透网络的发展。 (C) 2007 Elsevier Ltd. 保留所有权利。
Three different industrially available multiwalled carbon nanotube (MWNT) materials were directly incorporated into polycarbonate by melt mixing using a small-scale compounder. Despite of similar aspect ratios the electrical percolation behaviour was different. TEM investigations reveal significant differences in the nanotube dispersion which can be attributed to different dispersability of the raw MWNT materials. It is shown that the investigation of the sedimentation behaviour of aqueous MWNT dispersions is a simple method to estimate the nanotube dispersability.The relationships between melt processing conditions and MWNT dispersion and distribution were studied on polycarbonate samples containing 0.875 wt% MWNT prepared by masterbatch dilution. During melt mixing only high shear forces can provide suitable MWNT dispersion because firstly the MWNT disentanglement is facilitated and secondly secondary agglomeration is prevented. At low shear agglomeration of formerly well dispersed MWNT could be observed. During hot pressing the network or MWNT arrangement and the resulting electrical conductivity can be manipulated by the processing conditions like melt temperature and pressing speed. A certain nanotube agglomeration can enhance the development of an electrical percolated network as shown by dielectric spectroscopy. (C) 2007 Elsevier Ltd. All rights reserved.