Synthesis and properties of novel aromatic polyimides derived from bis(p-aminophenoxy)methylphenylsilane

A novel siloxane-containing diamine, bis(p-aminophenoxy)methylphenylsilane (BAMPS), was synthesized from the condensation of dichloromethylphenylsilane with p-aminophenol in the presence of triethylamine. A series of BAMPS-based aromatic polyimides were prepared from BAMPS and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure including ring-opening polyaddition to poly(amic acid)s and subsequent cyclodehydration to polyimides. The inherent viscosities of poly(amic acid)s III_a-III_f ranged from 0.09 to 0.36 dL g^-1 in N,N-dimethylacetamide at a concentration of 0.5 g dL^-1 at 30°C. The inherent viscosities of polyimides were between 0.06 and 0.32 dL g^-1 in various solvents at 30°C. Polyimides, especially IV_c and IV_b were soluble in a wide range of organic solvents such as N-methyl-2-pyrrolidinone, concentrated H₂SO₄. N.N-dimethylacetamide, N.N-dimethylfomamide, and dimethyl sulfoxide. The polyimides were characterized by elementary analysis, IR spectra. TGA, and DSC. They also had glass transition temperatures ranging from 128 to 181°C. The 10% mass loas temperature was recorded in the range of 404-443°C in nitrogen and of 315-339°C in oxygen.