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Preparation of Meldrum's acid‐functionalized polyimides exhibiting organo‐soluble, reactive, self‐crosslinkable, and colorless features
Author(s) -
Huang ChienHo,
Liu YingLing
Publication year - 2021
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20210112
Subject(s) - polyimide , polymer chemistry , solubility , materials science , diamine , glass transition , ketene , condensation polymer , nanocomposite , tetrahydrofuran , reactivity (psychology) , polymer , chemical engineering , chemistry , organic chemistry , nanotechnology , layer (electronics) , composite material , solvent , engineering , medicine , alternative medicine , pathology
Functional polyimides (PIs) having some desired properties, for example, organo‐solubility, chemical reactivity, crosslinkable feature, and high transparency in visible region, are attractive for specific applications. This work reports an effort to integrate the above‐mentioned properties in one polyimide through introduction of Meldrum's acid (MA) moieties to polyimide chains with using a MA‐containing diamine (MADA) as a monomer. The polyimide prepared with MADA and 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) (PI[MADA‐6FDA]) has a number‐averaged molecular weight of 56,800 g mol −1 , shows good solubility in tetrahydrofuran and aprotic high polar solvents, and exhibits post‐reactivity/crosslinkability through MA‐mediated ketene chemistry. Crosslinked PI(MADA‐6FDA) film shows a glass transition temperature of 289°C, a dielectric constant of about 2.78, and high flexibility bearing a near‐180° bending. The MA‐mediated ketene chemistry contributes to in situ building up covalent linkages between PI chains and silica nanoparticles (SNPs) in preparation of PI/SNPs nanocomposite films (NCF). Formation of the PI/SNPs NCFs enhances the thermal and mechanical properties, reduces the dielectric constants, and increases the transparency. The properties of the MA‐functionalized PI are attractive for further studies on their applications.