Duy Linh Nguyen Pham, Bui Chuong, Nguyen Liem Thanh, Nguyen Tung Huy, Tung Nguyen Thanh, La Duong Duc
Center for Polymer Composite and Paper, School of Chemical Engineering, Hanoi University of Science and Technology, Hai Ba Trung, Hanoi 100000, Vietnam.
Institute of Materials Science and Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18-Hoang Quoc Viet, Hanoi 100000, Vietnam.
Polymers (Basel). 2022 Jun 22;14(13):2541. doi: 10.3390/polym14132541.
Graphene has been extensively considered an ideal additive to improve the mechanical properties of many composite materials, including rubbers, because of its novel strength, high surface area, and remarkable thermal and electron conductivity. However, the pristine graphene shows low dispersibility in the rubber matrix resulting in only slightly enhanced mechanical properties of the rubber composite. In this work, graphene nanoplatelets (GNPs) were modified with dioctyl phthalate (DOP) to improve the dispersibility of the graphene in the natural rubber (NR). The distribution of the DOP-modified GNPs in the NR matrix was investigated using scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The effect of the modified GNPs' contents on the mechanical properties of the GNPs/NR composite was studied in detail. The results showed that the abrasion resistance of the graphene-reinforced rubber composite significantly improved by 10 times compared to that of the rubber without graphene (from 0.3 to 0.03 g/cycle without and with addition of the 0.3 phr modified GNPs). The addition of the modified GNPs also improved the shear and tensile strength of the rubber composite. The tensile strength and shear strength of the NR/GNPs composite with a GNPs loading of 0.3 phr were determined to be 23.63 MPa and 42.69 N/mm, respectively. Even the presence of the graphene reduced the other mechanical properties such as Shore hardness, elongation at break, and residual elongation; however, these reductions were negligible, which still makes the modified GNPs significant as an effective additive for the natural rubber in applications requiring high abrasion resistance.
由于石墨烯具有新颖的强度、高比表面积以及卓越的热导率和电子导电性，它已被广泛认为是一种理想的添加剂，可用于改善包括橡胶在内的许多复合材料的机械性能。然而，原始石墨烯在橡胶基体中的分散性较低，导致橡胶复合材料的机械性能仅略有增强。在这项工作中，用邻苯二甲酸二辛酯（DOP）对石墨烯纳米片（GNPs）进行改性，以提高石墨烯在天然橡胶（NR）中的分散性。使用扫描电子显微镜、X射线衍射和拉曼光谱研究了DOP改性的GNPs在NR基体中的分布。详细研究了改性GNPs含量对GNPs/NR复合材料机械性能的影响。结果表明，与不含石墨烯的橡胶相比，石墨烯增强橡胶复合材料的耐磨性显著提高了10倍（未添加和添加0.3 phr改性GNPs时分别为0.3和0.03 g/循环）。添加改性GNPs还提高了橡胶复合材料的剪切强度和拉伸强度。GNPs含量为0.3 phr的NR/GNPs复合材料的拉伸强度和剪切强度分别测定为23.63 MPa和42.69 N/mm。即使存在石墨烯会降低其他机械性能，如邵氏硬度、断裂伸长率和残余伸长率；然而，这些降低可以忽略不计，这仍然使得改性GNPs作为天然橡胶在需要高耐磨性的应用中的有效添加剂具有重要意义。
