Quantitative analysis of the formation mechanism of tightly bound rubber by using carbon-coated alumina nanoparticles as a model filler
Quantitative analysis of the formation mechanism of tightly bound rubber by using carbon-coated alumina nanoparticles as a model filler
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DOI：
10.1016/j.carbon.2020.11.074
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发表时间：
2021-03-01
期刊：
影响因子：
10.9
通讯作者：
Kyotani, Takashi
中科院分区：
文献类型：
--
作者：
Hoshikawa, Yasuto;Kawaguchi, Rei;Kyotani, Takashi
使用碳包覆的氧化铝纳米颗粒作为丁苯橡胶（SBR）的模型填料，制备具有不同碳表面化学的橡胶复合材料，并分析了在每个复合材料中形成的结合橡胶与碳表面化学的关系。本方法提供了在分子水平上对橡胶-碳界面的定量理解，从而提出了在与SBR混合过程中紧密结合的橡胶的形成机理如下。首先，发生SBR的强物理吸附，并且几乎所有填料表面（总表面的99.8%）被物理吸附的SBR的单分子层覆盖。然后使在该过程中形成的聚合物自由基逐渐与暴露的碳表面（总表面的0.2%）上的H-封端的边缘位点反应，并且所得的自由边缘位点化学键合到其它聚合物自由基上以形成化学吸附的聚合物。此外，本复合材料的独特结构使得可以用常规的差示扫描量热法分析紧密结合的橡胶的状态，这强烈地表明紧密结合的橡胶确实处于玻璃态。(C)2020爱思唯尔有限公司保留所有权利。
Using carbon-coated alumina nanoparticles as a model filler for styrene-butadiene rubber (SBR), rubber composites with different carbon surface chemistry were prepared and the bound rubber thus formed in each composite was analyzed in relation to the carbon surface chemistry. The present approach provides quantitative understanding of the rubber-carbon interface at the molecular level and thereby the formation mechanism of tightly bound rubber during a mixing process with SBR is proposed as follows. At first, the strong physisorption of SBR occurs and almost all the filler surface (99.8% of the total surface) is covered with a single-molecule layer of physisorbed SBR. The polymer radicals formed in the process are then gradually allowed to react with the H-terminated edge sites on the exposed carbon surface (0.2% of the total surface) and the resulting free edge sites are chemically-bonded to the other polymer radicals to form the chemisorbed polymer. Moreover, the unique structure of the present composites makes it possible to analyze the state of tightly bound rubber with the conventional differential scanning calorimetry, which strongly suggests that the tightly bound rubber is indeed in a glassy state. (C) 2020 Elsevier Ltd. All rights reserved.