铜颗粒的物理性能以及热和电稳定性可以通过表面保护来改善。这主要取决于涂层材料。我们的研究是,因此,专注于流变学,热,通过比较未涂覆(Cu),聚合物复合材料的机械和电学表征各种体积浓度(高达40%)的低密度聚乙烯中的银涂层(Cu@Ag)和二氧化硅涂层(Cu@Si)铜片。通过流变特性研究了颗粒之间的相互作用,因为这些表明网络形成(几何纠缠),这对于机械加固以及建立电通路(电渗透)是重要的。结果表明,Cu和Cu@Si的几何和电渗流相同,~15%,while,令人惊讶的是,Cu@Ag表现出低得多的渗滤,~7.5%,表明Ag涂层材料的熔化,这也降低了晶体生长(结晶度)。此外,对于所有研究的材料,流变和机械响应的大小保持相同,表明涂层材料不提供任何负载转移能力。然而,它们深刻影响电子转移,在这一点上,与Cu(1.7×10-4S/m)和Cu@Si(1.5×10-10S/m)相比,Cu@Ag表现出优异的电导率(74.4S/m)。获得的结果对于设计各种应用的先进聚合物复合材料非常重要,特别是在需要增强导电性的电子设备中。
The physical properties as well as thermal and electrical stability of copper particles can be improved by surface protection, which mainly depends on the coating material. Our study was, therefore, focused on the rheological, thermal, mechanical and electrical characterization of polymer composites by comparing uncoated (Cu), silver-coated (Cu@Ag) and silica-coated (Cu@Si) copper flakes in low-density polyethylene at various volume concentrations (up to 40%). Interactions among particles were investigated by rheological properties, as these indicate network formation (geometrical entanglement), which is important for mechanical reinforcement as well as establishing an electric pathway (electrical percolation). The results showed that geometrical and electrical percolation were the same for Cu and Cu@Si, ~15%, while, surprisingly, Cu@Ag exhibited much lower percolation, ~7.5%, indicating the fusion of the Ag coating material, which also decreased crystal growth (degree of crystallinity). Furthermore, the magnitude of the rheological and mechanical response remained the same for all investigated materials, indicating that the coating materials do not provide any load transfer capabilities. However, they profoundly affect electron transfer, in that, Cu@Ag exhibited superior conductivity (74.4 S/m) compared to Cu (1.7 × 10-4 S/m) and Cu@Si (1.5 × 10-10 S/m). The results obtained are important for the design of advanced polymer composites for various applications, particularly in electronics where enhanced electrical conductivity is desired.