Synthesis and comparative study on copolyetherimides from mixed isopropylidenebis(1,4-phenylene-oxy) bis(phthalic anhydride)s

Abstract

Mixed isopropylidenebis(1,4-phenylene-oxy) bis(phthalic anhydride)s with different ratios ( Mixed-BPADA 1-3 ) were synthesized successfully via aromatic nucleophilic substitution from nitrophthalonitrile and bisphenol A. The corresponding copolyetherimides (CoPEIs) were prepared with two representative aromatic diamines (4,4′-oxydianiline (4,4′-ODA) and m -phenylenediamine ( m -PDA)) via two-step procedure and chemical imidization. CoPEIs showed T g s from 222 to 256 °C and T d5% s from 486 to 505 °C in argon, good mechanical properties (tensile moduli of 2.5–2.9 GPa, tensile strengths of 69–96 MPa, and elongations at break of 3.3–6.3%), and good solubility. With the introduction of 3-substituted phthalimide unit, CoPEIs displayed higher T g values, lower elongations, better solubility and larger d -spacings. The rheological properties of thermoplastic polyimide resins based on the Mixed-BPADA were investigated. CoPEI-b series displayed good melt processibility, and the CoPEI-3b derived from Mixed-BPADA 3 and m -PDA had the lowest melt viscosity among the copolymers. Compared to isomeric PEIs derived from BPADA isomers, CoPEIs displayed lower melt viscosities, indicating that the melt processibility had been greatly improved. • Mixed BPADAs with different ratios of BPADA isomers were prepared by a simple method. • The isomeric effect on the properties of the copolyimides were well investigated. • The melt processibility of easily prepared copolyimides have been greatly improved.