Surface modification of copper-based flakes for conductive polymer composites

Mihelčič, Mohor (author), Oseli, Alen (author), Rojac, Tadej (author), Slemenik Perše, Lidija (author)

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.

• Language: English
• Keywords: polymer composites, copper flakes, silver coating, silica coating, percolation threshold, rheological properties, thermal properties, mechanical properties, electrical properties
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 14 str.
• Numbering: Vol. 16, iss. 12, art. 1620
• PID: 20.500.12556/RUL-158503
• UDC: 539.3:678
• ISSN on article: 2073-4360
• DOI: 10.3390/polym16121620
• COBISS.SI-ID: 198896899
• Publication date in RUL: 14.06.2024

Record is a part of a journal

• Title: Polymers
• Shortened title: Polymers
• Publisher: MDPI
• ISSN: 2073-4360
• COBISS.SI-ID: 517951257

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: polimerni kompoziti, bakrene luske, srebrna prevleka, silicijeva prevleka, perkolacijski prag, reološke lastnosti, termične lastnosti, mehanske lastnosti, električne lastnosti

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0264
• Name: Trajnostni polimerni materiali in tehnologije