Tailoring asymmetric filler arrangement by hollow glass microspheres towards polymer composites with improved through-plane thermal conductivity. (1st March 2023)

• Record Type: Journal Article
• Authors: Jin, Yucong; Ye, Lijun; Chai, Yuchi; Hong, Jiahui; Li, Yongjin
• Is Part Of: Composites science and technology. Volume 233(2023)
• Publication Date: 2023-03-01
• Subjects: Polymer-matrix composites (PMCs) -- Flake graphites -- Thermal properties -- Anisotropy -- Glass microspheres; Composite materials -- Periodicals; Composite materials; Fibrous composites; Periodicals; 620.118
• DOI: 10.1016/j.compscitech.2022.109904
• Languages: English
• ISSNs: 0266-3538

Abstract

Abstract: Highly anisotropic thermal conductivity, i.e ., a limited through-plane thermal conductivity ( λ ⊥ ), is normally observed in polymer composites with asymmetric fillers that are vulnerable to orientate along the flow field during melt-processing. We herein explored the possibility to tailor the filler arrangement and λ ⊥ of polymer composites with asymmetric fillers using nonconductive hollow glass microspheres (HGμS). The results showed that λ ⊥ of ultrahigh-filled polyamide 6/flake graphite (PA6/FG) composites with 70 wt% (54.7 vol%) FG increased by 27% instead of decreasing when replacing 3 wt% FG platelets with HGμS ( i.e ., 8.1 vol%, and 12.2 vol% HGμS with a diameter of 18 μm and 38 μm, respectively). The increase of λ ⊥ from diluting FG with HGμS was attributed to the reduced structural anisotropy of the FG network, i.e ., the in-plane orientation of FG platelets within the polymer matrix was inhibited. A synergistic effect on the improvement of λ ⊥ was achieved by replacing FG platelets with combination of HGμS and alumina (Al2 O3 ) microspheres. This synergy takes the effects from the "bridging" of FG platelets by Al2 O3 and the inhibiting of in-plane FG orientation by HGμS. Graphical abstract: Image 1