Since the discovery of carbon nanotubes, they have been intensely studied as filler materials into different matrices, including polymers to obtaining composites with enhancing properties. Carbon spheres are other type of nanostructures that have not been enough studied as reinforcement material. Polymeric composites with enhanced properties have gradually replaced many of the conventional materials in several areas. In this research, a comparative study of composites based in MWCNTs and CSs incorporated in poly(methyl methacrylate) matrices by mixing solution method was carried out. Composites with 2 wt%, 3 wt%, and 4 wt% of MWCNTs and CSs were obtained through solution mixing and were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Carbon sphere composites were observed with better dispersion than carbon nanotube composites through SEM. D, G, and G’ characteristic bands of carbon nanostructures and typical bands of PMMA were observed by Raman spectroscopy in all composites. C–H, C=O, and CH₂ vibrations were depicted in composites spectra by FTIR. Vickers microhardness and electrical conductivity of composites were measured. A significant increasing in electrical conductivity was obtained in MWCNTs/PMMA composites, reaching values up to 8.45 × 10^–5 S/cm. Nevertheless, the highest electrical conductivity values were observed in CSs composites (7.98 × 10^–4 S/cm). Vickers microhardness also was enhanced in all composites; however, CSs/PMMA composites showed the highest values in contrast with MWCNTs/PMMA composites. The major Vickers and electrical conductivity properties of CSs/PMMA composites are attributed to better carbon spheres dispersion into polymer matrix.

中文翻译：

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多壁碳纳米管和碳球与聚甲基丙烯酸甲酯合成的复合材料的电导率和维氏显微硬度：对比研究

自从发现碳纳米管以来，已经对其进行了深入研究，将其作为填充剂用于不同的基质中，包括聚合物，以获得具有增强性能的复合材料。碳球是其他类型的纳米结构，尚未得到足够的研究作为增强材料。具有增强性能的聚合物复合材料已在几个领域逐渐取代了许多传统材料。在这项研究中，通过混合溶液法对掺入聚甲基丙烯酸甲酯基体中的MWCNTs和CSs的复合材料进行了比较研究。通过溶液混合获得具有2wt％，3wt％和4wt％的MWCNT和CS的复合材料，并通过扫描电子显微镜（SEM），拉曼光谱和傅里叶变换红外光谱（FTIR）表征。通过SEM观察到碳球复合材料比碳纳米管复合材料具有更好的分散性。通过拉曼光谱法在所有复合材料中观察到了碳纳米结构的D，G和G'特征带和PMMA的典型带。C–H，C = O和CHFTIR在复合材料光谱中描绘了_2种振动。测量了复合材料的维氏显微硬度和电导率。MWCNTs / PMMA复合材料的电导率显着提高，达到8.45×10 ^–5 S / cm。然而，在CSs复合材料中观察到最高的电导率值（7.98×10 ^–4 S / cm）。所有复合材料的维氏显微硬度也得到了提高。然而，与多壁碳纳米管/聚甲基丙烯酸甲酯复合材料相比，CSs / PMMA复合材料表现出最高的价值。CSs / PMMA复合材料的主要维氏和导电性能归因于更好的碳球分散到聚合物基体中。