Nisar Muhammad, Galland Griselda Barrera, Geshev Julian, Bergmann Carlos, Quijada Raúl
Facultad de Ingeniería, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción 4090541, Chile.
Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, Brazil.
ACS Omega. 2023 Jun 8;8(24):21983-21995. doi: 10.1021/acsomega.3c01917. eCollection 2023 Jun 20.
Core-shell magnetic air-stable nanoparticles have attracted increasing interest in recent years. Attaining a satisfactory distribution of magnetic nanoparticles (MNPs) in polymeric matrices is difficult due to magnetically induced aggregation, and supporting the MNPs on a nonmagnetic core-shell is a well-established strategy. In order to obtain magnetically active polypropylene (PP) nanocomposites by melt mixing, the thermal reduction of graphene oxides (TrGO) at two different temperatures (600 and 1000 °C) was carried out, and, subsequently, metallic nanoparticles (Co or Ni) were dispersed on them. The XRD patterns of the nanoparticles show the characteristic peaks of the graphene, Co, and Ni nanoparticles, where the estimated sizes of Ni and Co were 3.59 and 4.25 nm, respectively. The Raman spectroscopy presents typical D and G bands of graphene materials as well as the corresponding peaks of Ni and Co nanoparticles. Elemental and surface area studies show that the carbon content and surface area increase with thermal reduction, as expected, following a reduction in the surface area by the support of MNPs. Atomic absorption spectroscopy demonstrates about 9-12 wt % metallic nanoparticles supported on the TrGO surface, showing that the reduction of GO at two different temperatures has no significant effect on the support of metallic nanoparticles. Fourier transform infrared (FT-IR) spectroscopy shows that the addition of a filler does not alter the chemical structure of the polymer. Scanning electron microscopy of the fracture interface of the samples demonstrates consistent dispersion of the filler in the polymer. The TGA analysis shows that, with the incorporation of the filler, the initial () and maximum () degradation temperatures of the PP nanocomposites increase up to 34 and 19 °C, respectively. The DSC results present an improvement in the crystallization temperature and percent crystallinity. The filler addition slightly enhances the elastic modulus of the nanocomposites. The results of the water contact angle confirm that the prepared nanocomposites are hydrophilic. Importantly, the diamagnetic matrix is transformed into a ferromagnetic one with the addition of the magnetic filler.
近年来，核壳型磁性空气稳定纳米颗粒越来越受到关注。由于磁诱导聚集，在聚合物基体中获得令人满意的磁性纳米颗粒（MNP）分布很困难，而将MNP负载在非磁性核壳上是一种成熟的策略。为了通过熔融共混获得具有磁活性的聚丙烯（PP）纳米复合材料，在两个不同温度（600和1000℃）下对氧化石墨烯（TrGO）进行了热还原，随后将金属纳米颗粒（Co或Ni）分散在其上。纳米颗粒的XRD图谱显示了石墨烯、Co和Ni纳米颗粒的特征峰，其中Ni和Co的估计尺寸分别为3.59和4.25nm。拉曼光谱呈现了石墨烯材料典型的D带和G带以及Ni和Co纳米颗粒的相应峰。元素和表面积研究表明，正如预期的那样，随着热还原，碳含量和表面积增加，同时由于MNP的负载表面积减小。原子吸收光谱表明，约9 - 12 wt%的金属纳米颗粒负载在TrGO表面，表明在两个不同温度下GO的还原对金属纳米颗粒的负载没有显著影响。傅里叶变换红外（FT - IR）光谱表明，填料的加入不会改变聚合物的化学结构。样品断裂界面的扫描电子显微镜显示填料在聚合物中分散均匀。TGA分析表明，随着填料的加入，PP纳米复合材料的初始（）和最大（）降解温度分别提高到34和19℃。DSC结果表明结晶温度和结晶度百分比有所提高。填料的加入略微提高了纳米复合材料的弹性模量。水接触角的结果证实所制备的纳米复合材料是亲水性的。重要的是，随着磁性填料的加入，抗磁性基体转变为铁磁性基体。
