Voznyakovskii Alexander, Vozniakovskii Aleksey, Kidalov Sergey
Institute for Synthetic Rubber, 198035 Saint-Petersburg, Russia.
Ioffe Institute, 194021 Saint-Petersburg, Russia.
Nanomaterials (Basel). 2022 Feb 16;12(4):657. doi: 10.3390/nano12040657.
For the first time, few-layer graphene (FLG) nanosheets were synthesized by the method of self-propagating high-temperature synthesis (SHS) from biopolymers (glucose, starch, and cellulose). We suggest that biopolymers and polysaccharides, particularly starch, could be an acceptable source of native cycles for the SHS process. The carbonization of biopolymers under the conditions of the SHS process was chosen as the basic method of synthesis. Under the conditions of the SHS process, chemical reactions proceed according to a specific mechanism of nonisothermal branched-chain processes, which are characterized by the joint action of two fundamentally different process-accelerating factors-avalanche reproduction of active intermediate particles and self-heating. The method of obtaining FLG nanosheets included the thermal destruction of hydrocarbons in a mixture with an oxidizing agent. We used biopolymers as hydrocarbons and ammonium nitrate as an oxidizing agent. Thermal destruction was carried out in SHS mode, heating the mixture in a vessel up to 150-200 °C at a heating speed of 20-30 °C/min and keeping at this temperature for 15-20 min with the discharge of excess gases into the atmosphere. A combination of spectrometric research methods, supplemented by electron microscopy data, has shown that the particles of the carbonated product powder in their morphometric and physical parameters correspond to FLG nanosheets. An X-ray diffraction analysis of the indicated FLG nanosheets was carried out, which showed the absence of formations with a graphite crystal structure in the final material. The surface morphology was also studied, and the IR absorption features of FLG nanosheets were analyzed. It is shown that the developed SHS method makes it possible to obtain FLG nanosheets with linear dimensions of tens of microns and a thickness of not more than 1-5 graphene layers (several graphene layers).
首次通过自蔓延高温合成（SHS）法从生物聚合物（葡萄糖、淀粉和纤维素）合成了少层石墨烯（FLG）纳米片。我们认为生物聚合物和多糖，特别是淀粉，可能是SHS过程中天然循环的可接受来源。选择在SHS过程条件下生物聚合物的碳化作为基本合成方法。在SHS过程条件下，化学反应按照非等温支链过程的特定机制进行，其特征是两种根本不同的过程加速因素——活性中间粒子的雪崩式繁殖和自热的共同作用。获得FLG纳米片的方法包括在与氧化剂的混合物中热破坏碳氢化合物。我们使用生物聚合物作为碳氢化合物，硝酸铵作为氧化剂。热破坏以SHS模式进行，在容器中将混合物加热至150 - 200°C，加热速度为20 - 30°C/分钟，并在此温度下保持15 - 20分钟，同时将过量气体排放到大气中。光谱研究方法与电子显微镜数据相结合表明，碳酸化产物粉末颗粒在形态和物理参数上与FLG纳米片相对应。对所示的FLG纳米片进行了X射线衍射分析，结果表明最终材料中不存在具有石墨晶体结构的形成物。还研究了表面形态，并分析了FLG纳米片的红外吸收特征。结果表明，所开发的SHS方法能够获得线性尺寸为几十微米且厚度不超过1 - 5个石墨烯层（几个石墨烯层）的FLG纳米片。
