Preparation of Boron Nitride-Coated Carbon Fibers and Synergistic Improvement of Thermal Conductivity in Their Polypropylene-Matrix Composites

• Published in: Polymers Vol. 11; no. 12; p. 2009
• Main Authors: Badakhsh, Arash, Han, Woong, Jung, Sang-Chul, An, Kay-Hyeok, Kim, Byung-Joo
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.12.2019; MDPI
• Subjects: Ammonia; Boron nitride; Carbon fiber reinforced plastics; Carbon fibers; Ceramic glazes; Chemical vapor deposition; Coating effects; Dielectric properties; Electrical resistivity; Fillers; Graphite; Heat conductivity; Heat transfer; Heat treatment; Nitrogen; Polymer matrix composites; Polymers; Polypropylene; Protective coatings; Thermal conductivity; X ray photoelectron spectroscopy; United States > US; Japan; carbon fiber; coating; boron nitride; thermal properties; polymer–matrix composites; electrical resistivity
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym11122009

The purpose of this study is to prepare boron nitride (BN)-coated carbon fibers (CF) and to investigate the properties of as-prepared fibers as well as the effect of coating on their respective polymer-matrix composites. A sequence of solution dipping and heat treatment was performed to blanket the CFs with a BN microlayer. The CFs were first dipped in a boric acid solution and then annealed in an ammonia-nitrogen mixed gas atmosphere for nitriding. The presence of BN on the CF surface was confirmed using FTIR, XPS, and SEM analyses. Polypropylene was reinforced with BN-CFs as the first filler and graphite flake as the secondary filler. The composite characterization indicates approximately 60% improvement in through-plane thermal conductivity and about 700% increase in the electrical resistivity of samples containing BN-CFs at 20 phr. An increase of two orders of magnitude in the electrical resistivity of BN-CF monofilaments was also observed.