Synthesis and properties of polyimides derived from 3,3',5,5'-tetramethyl-bis[4-(4-aminophenoxy)phenyl]sulfone

The novel diamine containing methyl-substituted arylene sulfone ether, 3,3'5,5'-tetramethylbis[4-(4-aminophenoxy)phenyl]sulfone (TBAPS), was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides tia a conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide (DMAc) to give poly(amic acid)s, followed by cyclodehydration to polyimides. The diamine was prepared through the nucleophilic displacement of bis(4-hydroxy-3,5-dimethylphenyl)sulfone with p-chloronitrobenzene in the presence of K-2 CO3, followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.80-1.72 dL g(-1). All the poly(amic acid)s could be cast from DMAc solutions and thermally converted into transparent, flexible and tough polyimide films. The polyimide films had a high tensile strength range 81-118 MPa, an elongation range at break 5-9% and a tensile modulus range 1.78-2.49 Cpa. The polyimide derived from 4,4'-hexafluoroisopropylidenebisphathalic anhydride had better solubility than the other polyimides. These polyimides had glass transition temperatures between 291-339 degrees C and 10% mass loss temperatures were recorded in the range 550-591 degrees C in nitrogen and 556-588 degrees C in air atmosphere. (C) 1997 Elsevier Science Ltd.