Polyimides Based on the Diethyltoluenediamine Isomer Mixture: Synthesis and Gas Transport Properties

Novel polyimides (PIs) based on the isomeric mixture of diethyltoluenediamine and 6FDA, BPDA, BTDA, ODPA, and BPADA dianhydrides are synthesized using a one-stage technique. The synthesized polymers possess high thermal stability and molecular weight, increased glass transition points T-g > 400 degrees C (except for PI with BPADA), and good film-forming properties. The polymers are soluble in chloroform, NMP, DMAA, and DMSO. The investigation of the gas transport of the synthesized polymers shows that the polyimides with 6FDA and BPDA dianhydride fragments can be assigned to the class of highly permeable polyimides (the oxygen permeability coefficients are 82 and 28 Barrer, respectively). The gas transport parameters of the synthesized polymers turn out to be comparableto those for the polyimides based on 2,4,6-trimethyl-m-phenylenediamine studied previously.