Synthesis of thermoplastic poly(ester-imide)s with excellent dimensional stability, good melt processability and high transparency

A series of poly(ester-imide)s (PEsIs) were synthesized by copolymerization of p -phenylene bis(trimellitate anhydride) (TAHQ), 4,4′-biphthalic dianhydride ( s -BPDA), and 2,2′-bis(trifluoromethyl)benzidine (TFDB) with different designed CF 3 -containing bisether-diamines. All of the PEsIs exhibited moderate glass transition temperatures ( T g s) in the range of 233–253 °C, low minimum melt viscosities of 506–3758 Pa·s, excellent dimensional stability with coefficient of thermal expansion (CTE) values of 30.4–37.1 ppm/K, and good optical properties ( T 450 of 84 %–86 %, T 850–1550 of 90 %). PEsI-IV exhibited the best comprehensive properties among the PEsIs, particularly with the lowest melt viscosity, excellent dimensional stability and high transmittance. These thermoplastic PEsIs with low CTE and high transparency have potential applications in the field of optical injection molding materials.