P-rGO/ENR复合材料的制备及其介电性能

Preparation and dielectric properties of P-rGO/ENR composites

  • 摘要: 高介电聚合物基复合材料因其介电性能优良、质轻、易加工等优点,在储能、传感和发电等领域具有广泛的应用前景。然而如何实现高介电常数和低介电损耗兼顾仍是目前该领域一项亟待解决的重要科学问题。为此,本文基于一种在填料与基体间“搭建桥梁”的策略,以氧化石墨烯(GO)为填料,环氧化天然橡胶(ENR)胶乳为基体,植酸(PA)为改性剂,通过乳液共混协同热压原位还原法制备了具有隔离结构的ENR基介电复合材料(P-rGO/ENR)。结果表明:PA作为“桥接”剂,分别与ENR和GO中的环氧基团发生了开环反应,大大增强了GO与ENR之间的界面作用。同时,在胶乳粒子的体积排斥效应下,GO纳米片自组装并包覆在ENR胶乳微球表面,最终GO相互连接并建立了良好的三维隔离网络。在100 Hz下,GO质量分数为2wt%时,P-rGO/ENR复合材料的介电常数高达569903,电导率也达到了10−4 S/cm,且介电损耗仍保持在较低水平(<5)。

     

    Abstract: Dielectric polymers have drawn great interest due to their applications in energy harvesting/storage devices, sensors and actuators owing to the merits of high breakdown strength, good flexibility, easy processing and low cost. However, how to achieve the combination of high dielectric constant and low dielectric loss is still an important scientific problem to be solved in this field. Therefore, based on a strategy of "bridges" effect between filler and matrix, this work prepared the epoxidized natural rubber (ENR) based dielectric composites (P-rGO/ENR) with segregated structure through latex blending and in-situ hot pressing reduction, using graphene oxide (GO) as filler, ENR latex as the matrix, and phytic acid (PA) as a modifying agent. The results show that PA can “bridge” GO and ENR by ring-opening reactions, respectively. As a result, the interfacial interaction between GO and ENR can be greatly enhanced. At the same time, the ENR latex particles force the GO nanosheets into the interstitial space between them because the ENR latex particles act as an excluded volume. As a result, GO nanosheets are self-assembled and coated on the surface of ENR latex microspheres. Finally, during the drying or co-coagulation procedure, these GO-coated ENR latex microspheres connect with each other to form a continuous three-dimensional segregated structure. The dielectric constant of the P-rGO/ENR composite (2wt%GO), is as high as 569903 and the conductivity is 10−4 S/cm as well as maintains a low dielectric loss (<5) at 100 Hz.

     

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