Effect of the melt processing conditions on the conductive paths formation in thermoplastic polyurethane/expanded graphite (TPU/EG) composites
Effect of the melt processing conditions on the conductive paths formation in thermoplastic polyurethane/expanded graphite (TPU/EG) composites
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DOI：
10.1016/j.compscitech.2013.03.002
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发表时间：
2013-05
影响因子：
9.1
通讯作者：
F. Piana;J. Pionteck
中科院分区：
文献类型：
--
作者：
F. Piana;J. Pionteck
以制备导电复合材料为目的，分析了熔体加工条件对热塑性聚氨酯(TPU)/膨胀石墨(EG)复合材料电渗流阈值浓度的影响。熔体混合和模压成型温度以及转速对电渗流浓度有显著影响。而在混合条件下，当得到均匀的复合材料时，渗流浓度在4wt.%以上，在仍有一定团聚的工艺条件下，达到较低的渗流浓度<；2wt.%(相当于<；1vol.%)。用两种不同的电极系统测定的电导率表明，表面附近区域的电阻增加。总体而言，与EG相比，复合材料的电导率较小。此外，EG使硬段成核，并影响热塑性弹性体的热性能和力学性能。
With the aim to produce electrically conductive composites, we analysed the influence of the melt processing conditions on the electrical percolation threshold concentration in thermoplastic polyurethane (TPU)/expanded graphite (EG) composites. Melt mixing and compression moulding temperature as well as rotational speed significantly affect the electrical percolation concentration. While at mixing conditions where a homogeneous composite is obtained the percolation concentration is above 4wt.%, lower percolation concentration of <2wt.% (corresponds to <1vol.%) was reached at processing conditions where a certain degree of agglomeration remained. The conductivities determined with two different electrode systems revealed increased resistance in the surface near regions. Overall, the conductivities of the composites are rather small if compared to that of EG. Furthermore, EG nucleates the crystallisation of the hard segments and affects the thermal and mechanical properties of TPU.