Chemistry and properties of imide oligomers end-capped with phenylethynylphthalic anhydrides

Abstract

A series of phenylethynyl-terminated imide oligomers were prepared by the reaction of aromatic dianhydride(s) with a stoichiometric excess of aromatic diamine(s) at calculated number average molecular weights of 1500–9000 g mol −1 and end-capped with phenylethynylphthalic anhydrides in N-methyl-2-pyrrolidinone. Unoriented thin films cured in flowing air to 350°C exhibited tensile strengths and moduli of 105.5–139.3 MPa and 2.8–3.2 GPa at 23°C, respectively, with good retention of properties at 177°C. Stressed film specimens exhibited excellent resistance to a variety of solvents after a 2 week exposure period at ambient temperature. One phenylethynyl-terminated imide oligomer was selected for more extensive evaluation and gave high fracture toughness, adhesive and composite properties. The chemistry, physical and mechanical properties of these materials are discussed.