Synthesis and characterization of organosoluble radiation-resistant composite materials from octa(maleimidophenyl)silsesquioxane and aryldiamines

Radiation-resistant composite materials based on nano-sized polyhedral oligomeric silsesquioxanes building blocks. We successfully synthesized via aspartimide linkages resulting from Michael addition of octa(maleimidophenyl)silsesquioxane (OMIPS) and aryldiamines OMIPS. These materials can serve as a nano building block for construction of materials with nanometer control of the periodicity of the organic and inorganic components. The monomer concentration and reaction time of polymerization are optimized, which were 0.047 mol L⁻¹ and 96 hours, respectively. The resulting polyaspartimides (PPAIs) were characterized by Fourier transform infrared, dielectric analysis, thermal properties, and morphological studies. The PPAI polymers are amorphous and soluble in highly polar organic solvents and show glass transition temperatures of 297°C to 323°C. They offer good thermal stability of 437°C to 507°C under nitrogen atmosphere, high char yields of 58% to 65% at 800°C, and have a dielectric constant of 3.7 to 4.1. Transition electron microscope analysis reveals the OMIPS dispersed well in molecular level in the continuous matrix while some aggregates also seen in the matrix. The UV radiation resistance of the resulting PPAI polymers was investigated.