Multi walled carbon nanotubes induced viscoelastic response of polypropylene copolymer nanocomposites: Effect of filler loading on rheological percolation
Multi walled carbon nanotubes induced viscoelastic response of polypropylene copolymer nanocomposites: Effect of filler loading on rheological percolation
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DOI：
10.1016/j.polymertesting.2016.08.001
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发表时间：
2016-10
期刊：
影响因子：
5.1
通讯作者：
P. Verma;M. Verma;Anju Gupta;Sampat Singh Chauhan;Rajender Singh Malik;V. Choudhary
中科院分区：
文献类型：
--
作者：
P. Verma;M. Verma;Anju Gupta;Sampat Singh Chauhan;Rajender Singh Malik;V. Choudhary
通过熔融加工制备具有0.2-7.0体积%多壁碳纳米管（MWCNT）的聚丙烯无规共聚物纳米复合材料。透射电子显微镜（TEM），以确定纳米尺度的碳纳米管的分散。采用平行板流变仪研究了这些纳米复合材料的线性粘弹性行为。与纯聚合物相比，碳纳米管的加入使复合材料的复数粘度（η*）、储能（G′）和损耗模量（G″）均有所提高，尤其是在低频区域，表明复合材料的行为从液态转变为固态。通过绘制储能模量与碳纳米管加载量的关系图并拟合幂律函数，在MWCNT的加载量为1.000.27体积%时观察到这些纳米复合材料中的流变逾渗阈值。然而，电逾渗阈值被报道在0.19体积%的多壁碳纳米管负载。在渗流阈值的差异被理解在纳米管连接与纳米管和聚合物链所需的导电性和流变渗流。
Polypropylene random copolymer nanocomposites having 0.2–7.0 vol% multi-walled carbon nanotubes (MWCNTs) were prepared via melt processing. Transmission electron microscopy (TEM) was employed to determine the nano scale dispersion of carbon nanotubes. Linear viscoelastic behavior of these nanocomposites was investigated using parallel plate rheometry. Incorporation of carbon nanotubes in the polymer matrix resulted in higher complex viscosity (η*), storage (G′) and loss modulus (G″) as compared to neat polymer, especially in the low-frequency region, suggesting a change from liquid to solid-like behavior in the nanocomposites. By plotting storage modulus vs. carbon nanotube loading and fitting with a power law function, the rheological percolation threshold in these nanocomposites was observed at a loading of ∼0.27 vol% of MWCNTs. However, electrical percolation threshold was reported at ∼0.19 vol% of MWCNTs loading. The difference in the percolation thresholds is understood in terms of nanotube connectivity with nanotubes and polymer chain required for electrical conductivity and rheological percolation.