Finely tuning polyimide film structure via green plasticizer's disentangling chain to improve the trade-off between transmittance and mechanical property

Abstract

To achieve the prevention of toxic waste while improving the intended functionality and durability of the film, polyimide (PI) based on TFMB-6FDA was tuned via the green plasticizer acetyl tributyl citrate (ATBC) to prepare a flexible film with high transmittance, high strength and ultraviolet (UV)-resistance. All the properties of ATBC tuned film (PI/T1, PI/T2, and PI/T3), average transmittance (AT), tensile strength (σb), elongation at break (ɛb), and elastic modulus (E) increase first and then decrease with the increase of ATBC amount. The three formers reach their own maximum values with 0.5 mole ratio of ATBC, 91.20 %, 244.0 MPa, and 12.2 %, respectively, higher than 90.50 %, 184.1 MPa, and 5.34 % of PI. The water contact angle of PI/T2 obtains the maximum value of 94.72°, and its water contact angle is 14.2 % higher than that of the pure PI (82.93°). The UV-resistance of PI/T2 is far better than that of PI after 2000 equivalent sun hours (ESHs) UV irradiation, and the AT attenuation of PI/T2 is just about one third of PI, so ATBC can retard the attenuation of PI transmittance and mechanical property.