A novel polyimide (PI) containing pendent biphenyl ester groups was synthesized from 3

5- diaminobenzoic-4’-biphenyl ester (DABBE) and 3

3’

4

4'-oxydiphthalie dianhydride (ODPA) by a one-step high-temperature polycondensafion in m-cresol．This PI is a semicrystalline polymer．Lots of short fine fibrie crystals with length and diameter about 20 μm and 1 μm respectively disperse randomly in the PI film．The optical textures and the X-ray diffraction patterns of the PI solution and film show that the PI main chains arc in the extended conformation and pack parallel to each other

and the pendent biphenyl ester groups occupy the space between the main chain layers

more or less perpendicular to the main chains．At the same time

mechanical and thermally stable properties of the PI film were investigated．The exceUent mechanical properties of general polyimide films arc reasonably maintained．the polyimide film with pendent groups showes higher tensile strength and modulus and lower Tg. TGA study showes a typical two-step weight loss behavior corresponding to the pyrolysis of pendent groupsand nlain chains of the PI

respectively．