Toughened polymer composites with flake carbonyl iron powders and their electromagnetic/absorption properties

► The selected flake carbonyl iron powders (FCIs) were investigated. ► We monitored the curing process of toughen polymer by FTIR. ► Effective permittivity εr and permeability μr of composite specimens were measured and discussed. ► Microwave absorption property of composites was calculated. Toughened polymer was prepared as the polymer matrix of electromagnetic/absorption materials in this paper. The selected flake carbonyl iron powders (FCIs) were introduced into polymer matrix as absorber, and investigated by morphological, static magnetic, crystal structural, and surface chemical state characterization. The curing process of toughened polymer was monitored by FT-IR. The chemical bonds resulting in rheological properties of polymer composites were formed between resin and polyurethane during the phase evolution from liquid to solid. The stress–strain curve of the polymer matrix indicated a toughened effect. Besides, the shrinkage properties of the toughened polymer were investigated through the measurement of resistivity. Effective permittivity (εr=ε′-jε″) and permeability (μr=μ′-jμ″) of the polymer composites with various FCIs content were measured and promised high impedance matching and low reflection loss with light absorber mass at Ku-band.