Fabrication and investigations on BMI/OMMT nanocomposites with superior high-temperature wave-transparent performance

In this work, stearyltrimethylammoium bromide (STAB) was used to modify montmorillonite (MMT). Subsequently, the modified organic montmorillonite (OMMT) was added into 4,4 '-Bismaleimidodiphenyl methane (BDM) and 2,2 '-Diallylbisphenol A (DBA) copolymerization system to prepare BDM/OMMT wave-transparent nanocomposites with 0-5 wt% OMMT content. It is found that the addition of OMMT improves the microstructure, thermal properties, and wave-transparent properties of BDM composites. At the addition of 2 wt%, the thermal stability of the resin system is the best, and the fracture morphology changes from brittle fracture characteristics to ductile fracture characteristics. Meanwhile, in X-band (8-12 GHz), OMMT-2 wt% with the thickness less than 2 mm or within 8-10 mm has excellent transmittance (> 90%). Moreover, the effect of temperature change on the wave-transparent performance of BDM/OMMT nanocomposites is investigated. From room temperature to 200 degrees C, the stability of high-temperature transmittance of OMMT-2 wt% is enhanced, and it still has good transmittance (> 90%) within in a wide thickness range at 200 degrees C. The enhancement of these properties is closely correlated with the interaction interface formed between OMMT and BDM resin matrix. The addition of OMMT can increase the design selection of BDM resin system and expand its application as a wave-transparent material.