Synthesis and property of fluorinated polyimides with double bond end groups for UV-cured coating

The fluorinated polyimides with double bond end groups (G-FPIs) based on 4,4′-(hexafluoroisopropylidene) diphthalic anhydride, 4,4′-(hexafluoroisopropylidene) dianiline, 4-aminobenzoic acid and glycidyl methacrylate were synthesized via a typical two-step imidization method. The structure and properties of G-FPIs were characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1HNMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). It was determined that all G-FPIs were the amorphous phase and easily soluble in many polar organic solvents, and the G-FPIs had high glass-transition temperature (Tg). Then, UV-curable coatings were prepared from G-FPIs, and the properties were evaluated by real-time fourier transform infrared (RTIR), thermogravimetric analysis (TGA), UV–vis spectroscopy, water contact angle and water absorption test. Results showed that these coatings possessed favorable double bond conversion, excellent thermal stability, higher optical transparency and lower moisture uptakes. Moreover, the coatings exhibited good hardness and excellent gloss. Due to the outstanding combination properties, these UV-cured coatings based on G-FPIs could be considered as potential candidates for photoelectric, microelectronic and aerospace materials.