The Processing and Electrical Properties of Isotactic Polypropylene/Copper Nanowire Composites

Po-Wen Lu; Chonlachat Jaihao; Li-Chern Pan; Po-Wei Tsai; Ching-Shuan Huang; Agnese Brangule; Aleksej Zarkov; Aivaras Kareiva; Hsin-Ta Wang; Jen-Chang Yang

doi:10.3390/polym14163369

The Processing and Electrical Properties of Isotactic Polypropylene/Copper Nanowire Composites

Polymers (Basel). 2022 Aug 18;14(16):3369. doi: 10.3390/polym14163369.

Authors

Po-Wen Lu^{1

2}, Chonlachat Jaihao², Li-Chern Pan³, Po-Wei Tsai⁴, Ching-Shuan Huang⁵, Agnese Brangule⁶, Aleksej Zarkov⁷, Aivaras Kareiva⁷, Hsin-Ta Wang⁴, Jen-Chang Yang^{8

9

10

11}

Affiliations

¹ Division of Gastroenterology and Hepatology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Zhongzheng Rd., Zhonghe, Taipei 23561, Taiwan.
² Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11052, Taiwan.
³ Graduate Institute of Biomedical Optomechatronics, Taipei Medical University, Taipei 110-31, Taiwan.
⁴ Institute of Organic & Polymeric Materials, National Taipei University of Technology, Taipei 106, Taiwan.
⁵ School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110-31, Taiwan.
⁶ Department of Pharmaceutical Chemistry, Riga Stradins University, LV-1007 Riga, Latvia.
⁷ Institute of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania.
⁸ International Ph.D. Program in Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 110-31, Taiwan.
⁹ Research Center of Biomedical Device, Taipei Medical University, Taipei 110-31, Taiwan.
¹⁰ Research Center of Digital Oral Science and Technology, Taipei Medical University, Taipei 110-31, Taiwan.
¹¹ Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110-31, Taiwan.

Abstract

Polypropylene (PP), a promising engineering thermoplastic, possesses the advantages of light weight, chemical resistance, and flexible processability, yet preserving insulative properties. For the rising demand for cost-effective electronic devices and system hardware protections, these applications require the proper conductive properties of PP, which can be easily modified. This study investigates the thermal and electrical properties of isotactic polypropylene/copper nanowires (i-PP/CuNWs). The CuNWs were harvested by chemical reduction of CuCl₂ using a reducing agent of glucose, capping agent of hexadecylamine (HDA), and surfactant of PEG-7 glyceryl cocoate. Their morphology, light absorbance, and solution homogeneity were investigated by SEM, UV-visible spectrophotometry, and optical microscopy. The averaged diameters and the length of the CuNWs were 66.4 ± 16.1 nm and 32.4 ± 11.8 µm, respectively. The estimated aspect ratio (L/D, length-to-diameter) was 488 ± 215 which can be recognized as 1-D nanomaterials. Conductive i-PP/CuNWs composites were prepared by solution blending using p-xylene, then melt blending. The thermal analysis and morphology of CuNWs were characterized by DSC, polarized optical microscopy (POM), and SEM, respectively. The melting temperature decreased, but the crystallization temperature increasing of i-PP/CuNWs composites were observed when increasing the content of CuNWs by the melt blending process. The WAXD data reveal the coexistence of Cu₂O and Cu in melt-blended i-PP/CuNWs composites. The fit of the electrical volume resistivity (ρ) with the modified power law equation: ρ = ρ_o (V - Vc)^-t based on the percolation theory was used to find the percolation concentration. A low percolation threshold value of 0.237 vol% and high critical exponent t of 2.96 for i-PP/CuNWs composites were obtained. The volume resistivity for i-PP/CuNWs composite was 1.57 × 10⁷ Ω-cm at 1 vol% of CuNWs as a potential candidate for future conductive materials.

Keywords: copper nanowires; isotactic polypropylene; percolation threshold; power law.

Grants and funding

MOST 110-2224-E-038-001/Ministry of Science and Technology