Dianhydride architectural effects on the relaxation behaviors and thermal and optical properties of organo-soluble aromatic polyimide films

Synthesis and Properties of Novel Melt Processable Isomeric Polythioetherimides

A series of 3,3’,4,4’-diphenylthioethertetracarboxylic dianhydride (s-TDPA), 2,3,3’,4’ -diphenylthioethertetracarboxylic dianhydride (a-TDPA), and 2,2’,3,3’-diphenylthioethertetracarboxylic dianhydride (i-TDPA) isomer mixtures were synthesized from 3- and 4-chlorophthalic anhydrides. Copolythioetherimides derived from TDPAs with different ratios of the isomers and 4,4’-oxydianiline (ODA) were prepared by a two-step polycondensation procedure. Solubility, thermal properties, mechanical properties and melt processability of copolythioetherimides were investigated and compared with corresponding homopolyimides. The dependence of these properties on the composition of TDPA isomers and the effects of molecular structures were discussed in this work in order to obtain an indication for the molecular design of high performance melt-processable polyimides.

Synthesis and Characterization of New Optically Active Poly (ethyl L-lysinamide)s and Poly (ethyl L-lysinimide)s

Ethyl L-lysine dihydrochloride was reacted with three different dianhydrides to yield the poly (ethyl L-lysinimide)s (PI(1-3)); it was also reacted with two different diacyl chlorides to yield the poly (ethyl L-lysinamide)s (PA(4-5)). The resulting polymers have inherent viscosities in the range of 0.15 to 0.42 dL g(-1). These polymers are prepared from an inexpensive starting material and are optically active, potentially ion exchangeable, semicrystalline, thermally stable, and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc, and sulfuric acid. All of the above polymers were fully characterized by FT-IR and (1)H NMR spectroscopy, elemental analysis, WAX diffraction, TGA, inherent viscosity measurement, and specific rotation.

Organosolubility and optical transparency of novel polyimides derived from 2′,7′-bis(4-aminophenoxy)-spiro(fluorene-9,9′-xanthene)

A series of polyimides were synthesized via a polycondensation of 2′,7′-bis(4-aminophenoxy)-spiro(fluorene-9,9′-xanthene) with aromatic tetracarboxylic dianhydrides. They exhibited a low dielectric constant, low moisture absorption, excellent solubility, high glass transition temperatures and high optical transparency.