Oriented ultra-high molecular weight polyethylene/gold nanocomposites: Electrical conductivity and chain entanglement dynamics
Oriented ultra-high molecular weight polyethylene/gold nanocomposites: Electrical conductivity and chain entanglement dynamics
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DOI：
10.3144/expresspolymlett.2021.42
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发表时间：
2021-06-01
影响因子：
3.3
通讯作者：
Ronca, S.
中科院分区：
文献类型：
--
作者：
Drakopoulos, S. X.;Psarras, G. C.;Ronca, S.
利用介电谱研究了金纳米粒子修饰的超高分子量聚乙烯纳米复合材料在向熔融态转变过程中的纠缠动力学。直流传导通过介电常数的对数导数近似计算，并观察到随着纠缠的形成而减少。随着拉伸比的增加，缠结的逐步形成导致更强的直流电导率下降，由于在预熔体结晶和部分取向的无定形链段的取向的损失。此外，在没有直流电导率的情况下获得尖锐的峰，这归因于金纳米颗粒和聚合物链之间的Maxwell-Wagner-Sillars（MWS）界面极化的偶极贡献。的MWS界面极化的弛豫时间增加的纠缠的逐步形成，如在先前的研究中观察到的。研究结果揭示了取向超高分子量聚乙烯纳米复合材料中缠结的形成过程。
Entanglement dynamics of uniaxially-oriented, disentangled ultra-high molecular weight polyethylene nanocom-posites modified with gold nanoparticles are investigated, using dielectric spectroscopy, during the transition to melt state. The dc conduction is approximately calculated via the logarithmic derivative of dielectric permittivity and is observed to decrease with the formation of entanglements. As the draw ratio increases, the progressive formation of entanglements resulted in a stronger dc conductivity decrease due to the loss of orientation in the pre-melt crystalline and partially oriented amorphous chain segments. Additionally, a sharp peak is obtained in the absence of dc conductivity, attributed to the dipolar contribution of the Maxwell-Wagner-Sillars (MWS) interfacial polarization between the gold nanoparticles and the polymer chains. The relaxation time of the MWS interfacial polarization increases with the progressive formation of entanglements, as observed in a previous study. The results presented shed light on the process of entanglement formation in oriented ultra-high molecular weight polyethylene nanocomposites.