Abstract

Since biochar is a renewable source of carbon, it has been examined as a substitute for carbon black as rubber composite filler. Although biochar can approach carbon black in terms of carbon and ash content, substituting carbon black with biochar typically degrades the mechanical properties of rubber composites because of the much larger particle size of biochar. Biochar is produced from biomass and must be size reduced by “top-down” methods such as milling. Thus, biochar frequently has populations of particles greater than 10 µm in diameter, which greatly reduce reinforcement properties by introducing localized stresses in the rubber composite. In this work we explore using nanosilica as a co-milling material with biochar as a means to reduce its particle size and consequently improve its ability to replace carbon black as rubber composite filler. Biochar co-milled with 1 wt% nanosilica was able to replace 40% of the carbon black filler in a styrene–butadiene rubber composite with virtually no loss in tensile strength. Also, elongation and toughness properties of the optimal biochar substituted composites were improved by over 31 and 24%, respectively.

中文翻译：

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纳米二氧化硅降低生物炭粒径及其对橡胶复合材料增强的影响

摘要

由于生物炭是一种可再生的碳源，因此已经研究过将其用作橡胶复合填料替代炭黑的方法。尽管就碳和灰分含量而言，生物炭可以接近炭黑，但是由于生物炭的粒径大得多，因此用生物炭代替炭黑通常会降低橡胶复合材料的机械性能。生物炭是由生物质生产的，必须通过“自上而下”的方法（例如研磨）减小尺寸。因此，生物炭通常具有直径大于10 µm的颗粒，这会通过在橡胶复合材料中引入局部应力而大大降低补强性能。在这项工作中，我们探索使用纳米二氧化硅作为与生物炭共同研磨的材料，以减少其粒径并因此提高其替代炭黑作为橡胶复合填料的能力。与1 wt％纳米二氧化硅共同研磨的Biochar能够代替苯乙烯-丁二烯橡胶复合材料中40％的炭黑填料，而拉伸强度几乎没有损失。而且，最佳生物炭取代的复合材料的伸长率和韧性性能分别提高了31％和24％以上。