天然橡胶共混物中超导电炭黑的偏聚及其对电磁性能的影响

Preferential localizations of super-conductive carbon black in natural rubber compounds and their effects on the electromagnetic properties of materials

采用机械共混法,在天然橡胶(NR)、环氧化天然橡胶(ENR)及其1∶1的共混物(NR/ENR)中添加超导电炭黑(SCCB),制备电磁屏蔽橡胶复合材料,研究了SCCB含量和基体极性差异对复合材料结构和电磁性能的影响。结果表明,随着SCCB含量增加,复合材料导电率(σ)和电磁屏蔽效能(EMI SE)逐渐增大,σ和EMI SE变化符合基于填料浓度的"逾渗"行为,并呈现以吸收为主导的电磁屏蔽机制;由于NR与ENR极性差异诱导的SCCB选择性分布,SCCB/NR/ENR复合材料具有最优的电磁性能,即最低的逾渗值(2.11%(体积分数))和最高的EMI SE(5.33 d B)。此外,还讨论了电磁性能与SCCB联通性之间的关系。

Super-conductive carbon black （SCCB）was incorporated into natural rubber （NR）,epoxidized natural rubber （ENR）and their bend （NR/ENR）to fabricate electromagnetic interference shielding composites via tow-roll mixing.The influences of SCCB contents and matrices nature on the microstructures and electromag-netic properties were systematically investigated.As the results shown,the conductivity and electromagnetic in-terference shielding effectiveness （EMI SE）of all composites gradually increased with the increasing of SCCB contents,presenting obvious percolation behavior and absorption-dominated shielding mechanism.Due to the polarity difference-induced preferential localization of SCCB in NR/ENR blend,the SCCB/NR/ENR showed the greatest improvements in electromagnetic properties,i.e.lowest percolation threshold of 2.1 1vol% （4.0wt%）, highest EMI SE of 5.33 dB.Also,the relation between electromagnetic properties and SCCB connectivity was discussed.