Microwave Properties of Composite Films Based on Polyvinyl Chloride and Brominated Activated Carbon

Abstract

Brominated activated carbon (AC/Br2) powder was used as a filler in poly(vinyl chloride) (PVC) to prepare PVC‐based composite films by hot pressing. The AC/Br2 filler was obtained by liquid phase bromination and contained both oxygen and bromine. In comparison with the unmodified AC, the AC/Br2 was subjected to thermogravimetric analysis in air and argon and temperature‐programmed desorption mass spectrometry in vacuum, which identified carbon‐oxygen and bromine groups and showed the comparable thermal stability of AC/Br2 and AC. XPS shows the predominance of phenolic groups among the carbon‐oxygen groups. Scanning electron microscopy and transmission electron microscopy showed preserved morphology and microstructure, while N2 adsorption showed a microporosity decrease after bromination. FTIR analysis suggested non‐chemical interactions between PVC and AC/Br2. As the AC/Br2 content in the PVC‐based composite films increases from 0.2 to 30 wt %, the electromagnetic radiation (EMR) reflection at Ka‐band microwave frequencies increases. To reduce the EMR reflection, the proposed composite films should contain a maximum of 0.2 wt % AC/Br2. The results indicate that the microwave properties of PVC‐based composite films can be tuned by adjusting the AC/Br2 content.