Synthesis of aromatic poly(urea-imide)with heteo-cyclic side chain structure

摘要

The poly(urea-imide)copolymers with inherent viscosity of 0.81-1.08 dl/g were synthesized by reacting aryl ether diamine or its polyurea prepolymer with various diisocyanate-terminated polyimide prepolymers.The aryl ether diamine was obtained by first nucleophilic substitution of phenolphthale in with rho-chloronitrobenzene in the presence of anhydrous potassium carbonate to form a dinitro aryl ether,and then further hydrogenated to diamine.The polyimide prepolymers were prepared by using 4,4'-diphenylmethane diisocyanate to react with pyromellitic dianhydride 3,3',4,4'-benzophenonetetracarboxylic dianhydride,or 3,3',4,4'-sulfonyldiphthalic anhydride by using the direct one-pot method to improve their solubility,but without sacrificing thermal property.These copolymers are amorphous,and readilysoluble in a wide rangeof organic solvents such as N-methyl-2-pyrrolidone,dimethylimidazole,N,N-dimethylacetamide,dimethyl sulfoxide,N,N-dimethylformamide,m-cresol,and sulfolane.All thepoly(urea-imides) have glass transition temperatures in the range of 205-240degC and show a 10 wt% loss at 326-352degC in nitrogen and 324-350degC in air.The tensile strength,elongation at break,and initial modulus of these copolymer films range from 42 to 79 MPa,5 to16%,and 1.23 to2.02 GPa,respectivley.