Damampai Kriengsak, Pichaiyut Skulrat, Stöckelhuber Klaus Werner, Das Amit, Nakason Charoen
Department of Rubber Technology, Faculty of Science & Industrial Technology, Prince of Songkla University, Surat Thani 84000, Thailand .
Leibniz-Institut für Polymerforschung Dresden e.V., D-01069 Dresden, Germany.
Polymers (Basel). 2022 Oct 18;14(20):4392. doi: 10.3390/polym14204392.
Natural rubber with 50 mol % epoxidation (ENR-50) was filled with carbon nanotubes (CNTs) and conductive carbon black (CCB) hybrid fillers with various CCB loadings of 2.5, 5.0, 7.0, 10.0 and 15.0 phr, and the compounds were mixed with ferric ion (Fe) as a crosslinking agent. The ENRs filled exclusively with CNTs, and CNT-CCB hybrid fillers exhibited typical curing curves at different CCB loadings, i.e., increasing torque with time and thus crosslinked networks. Furthermore, the incorporation of CNT-CCB hybrid fillers and increasing CCB loadings caused an enhancement of tensile properties (modulus and tensile strength) and crosslink densities, which are indicated by the increasing torque difference and the crosslink densities. The crosslink densities are determined by swelling and temperature scanning stress relaxation (TSSR). Increasing CCB loadings also caused a significant improvement in bound rubber content, filler-rubber interactions, thermal resistance, glass transition temperature () and electrical conductivity. A combination of 7 phr CNT and CCB with loading higher than 2.5 phr gave superior properties to ENR vulcanizates. Furthermore, the secondary CCB filler contributes to the improvement of CNT dispersion in the ENR matrix by networking the CNT capsules and forming CNT-CCB-CNT pathways and thus strong CNT-CCB networks, indicating the improvement in the tensile properties, bound rubber content and dynamic properties of the ENR composites. Moreover, higher electrical conductivity with a comparatively low percolation threshold of the hybrid composites was found as compared to the ENR filled with CNTs without CCB composite. The superior mechanical and other properties are due to the finer dispersion and even distribution of CNT-CCB hybrid fillers in the ENR matrix.
将50摩尔%环氧化的天然橡胶（ENR - 50）用碳纳米管（CNT）和导电炭黑（CCB）混合填料填充，CCB的填充量分别为2.5、5.0、7.0、10.0和15.0 phr，并且将这些胶料与作为交联剂的铁离子（Fe）混合。仅用CNT填充的ENR以及CNT - CCB混合填料在不同CCB填充量下呈现出典型的硫化曲线，即扭矩随时间增加，从而形成交联网络。此外，加入CNT - CCB混合填料以及增加CCB填充量会使拉伸性能（模量和拉伸强度）和交联密度增强，这通过扭矩差值增加和交联密度得以体现。交联密度通过溶胀和温度扫描应力松弛（TSSR）来测定。增加CCB填充量还会使结合橡胶含量、填料 - 橡胶相互作用、耐热性、玻璃化转变温度（）和电导率显著提高。7 phr的CNT与高于2.5 phr的CCB组合赋予ENR硫化胶优异的性能。此外，二次加入的CCB填料通过使CNT胶囊网络化并形成CNT - CCB - CNT路径，从而形成强大的CNT - CCB网络，有助于改善CNT在ENR基体中的分散，这表明ENR复合材料的拉伸性能、结合橡胶含量和动态性能得到改善。而且，与未添加CCB的CNT填充ENR复合材料相比发现，混合复合材料具有更高的电导率以及相对较低的渗滤阈值。优异的机械性能和其他性能归因于CNT - CCB混合填料在ENR基体中更精细的分散和均匀分布。
