Microwave absorbing and mechanical properties of alternating multilayer carbonyl iron powder-poly(vinyl chloride) composites

Polymeric composites filled with magnetic absorbents have been used extensively as microwave absorbing materials. However, their high filler content obstructed the application. In order to optimize the filler content and further improve the microwave absorbing properties, alternating multilayer carbonyl iron powder (CIP)/poly(vinyl chloride) (PVC) composites were designed and prepared by stacking neat PVC and CIP filled PVC alternately. The microwave absorbing properties were theoretically calculated by the transmission line theory and experimentally measured by the arch method, respectively. The experimental results were consistent with the calculated ones, which demonstrated that the alternating multilayer structure design can significantly improve the microwave absorbing property without increasing the filler content. The consistent results also demonstrated that the reflection loss (R-L) of the multilayer composites was strongly dependent on the layer number and layer arranging sequence. The minimum R-L (R-L-min) and effective bandwidth were exponentially dependent on the layer number. And the dependencies of the R-L-min and effective bandwidth on layer number exhibited a regularity reversal phenomenon when different layers faced to the incident wave. The mechanical property test showed that the alternating multilayer composites possessed enhanced tensile strength and elongation at break as the layer number increased. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45846.