Preparation and characterization of carbonyl iron powder/millable polyurethane elastomer microwave absorbing patch

Abstract

A microwave absorbing patch (MAP) was prepared by compounding millable polyurethane elastomer (MPU) and carbonyl iron powder (CIP). Surfaces of CIP were modified using silane coupling agents (SCA). The effects of different types and amounts of SCA, the amount of vulcanizing agent and the amount of CIP on the microstructure and mechanical properties were investigated. SCA was found to improve the interface compatibility between MPU and CIP and also reinforced the mechanical properties of MAP. The KH550 was the best modifier, and the optimal dosage of KH550 was 2% of the mass of CIP based on a comparison of tensile properties. The optimal dosage of the vulcanizing agent DDPH was 3% of the mass of MPU. However, a large number of CIP could be filled into MPU. The maximum filling content of CIP increased with the increasing Mooney viscosity of MPU, and the maximum filling content of CIP was 1200% of the mass of MPU. The electromagnetic parameters and reflection loss of MPU absorbers and MPU filled with CIP absorbers were measured in the 1–18 GHz frequency range. The absorbers of MPU filled with CIP had excellent microwave absorbing properties compared with the absorbers of MPU. POLYM. COMPOS., 35:1318–1324, 2014. © 2013 Society of Plastics Engineers