Synthesis and properties of thermoplastic polyetherimide resins modified by 1,4-bis(2,3-dicarboxyphenoxy)-2-tert-butylbenzene dianhydride (3,3′-TBHQDA)

Abstract

In order to prepare thermoplastic polyimide (PI) resins with good comprehensive performances, the modification of thermoplastic polyetherimides (PEIs) by 1,4-bis(2,3-dicarboxyphenoxy)-2-tert-butylbenzene dianhydride (3,3′-TBHQDA) was systematically investigated. The PEI-a-x and PEI-b-x series of polyetherimides were synthesized by chemical imidization of the diamine monomer m-phenylenediamine (m-PDA) with different contents of 1,4-bis(3,4-dicarboxyphenoxy)-2-tert-butylbenzene dianhydride (4,4′-TBHQDA) and 3,3′-TBHQDA or 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (4,4′-BPADA) and 3,3′-TBHQDA. These PEIs had glass transition temperatures (Tgs) in the range of 217–264 °C, low melt viscosities of 79–2367 Pa s, good transmittances of 87–88 % at 450 nm, and displayed good mechanical properties with tensile modulus of 2.8–3.2 GPa, tensile strengths of 89.6–118.4 MPa, and elongations at break of 3.9–6.4 %. The introduction of 3,3′-TBHQDA successfully improved thermal properties and melt processability of the PEIs. Among them, PEI-a-50 and PEI-b-50 displayed better comprehensive performances in PEI-a-x and PEI-b-x series, respectively, with moderate Tgs (256 and 249 °C, respectively), extremely low melt viscosities (161 and 297 Pa s at 400 °C, respectively), high transmittances at 450 nm (87 %), and good mechanical properties (tensile modulus of 3.1 and 2.8 GPa, tensile strengths of 105.6 and 106.3 MPa, respectively).