Synthesis and properties of soluble aromatic polyimides from novel 4,5-diazafluorene-containing dianhydride

A dianhydride monomer containing 4,5-diazofluorene was synthesized, and the corresponding organo-soluble polyimides exhibited good comprehensive properties.

Highly optical transparency and thermally stable polyimides containing pyridine and phenyl pendant

In order to obtain highly optical transparency polyimides, two novel aromatic diamine monomers containing pyridine and kinky structures, 1,1-bis[4-(5-amino-2-pyridinoxy)phenyl]diphenylmethane (BAPDBP) and 1,1-bis[4-(5-amino-2-pyridinoxy)phenyl]-1-phenylethane (BAPDAP), were designed and synthesized. Polyimides based on BAPDBP, BAPDAP, 2,2-bis[4-(5-amino-2-pyridinoxy)phenyl]propane (BAPDP) with various commercial dianhydrides were prepared for comparison and structure-property relationships study. The structures of the polyimides were characterized by Fourier transform infrared (FT-IR) spectrometer, wide-angle X-ray diffractograms (XRD) and elemental analysis. Film properties including solubility, optical transparency, water uptake, thermal and mechanical properties were also evaluated. The introduction of pyridine and kinky structure into the backbones that polyimides presented good optical properties with 91-97% transparent at 500 nm and a low cut-off wavelength at 353-398 nm. Moreover, phenyl pendant groups of the polyimides showed high glass transition temperatures (Tg ) in the range of 257-281 °C. These results suggest that the incorporating pyridine, kinky and bulky substituents to polymer backbone can improve the optical transparency effectively without sacrificing the thermal properties.

Highly transparent and organosoluble polyimides derived from 2,2′-bis[4-(5-amino-2-pyridinoxy) phenyl] propane

Two new isomers containing pyridine ring diamine monomers, 2,2′-bis[4-(5-amino-2-pyridinoxy)phenyl] propane (1b) and 2,2′-bis[4-(6-amino-3-pyridinoxy)phenyl] propane (2b), were prepared via a simple nucleophilic reaction of 2-chloro-5-nitropyridine and 5-bromo-2-nitropyridine with bisphenol A in the presence of potassium carbonate, respectively. A series of polyimides (PIs) were obtained from the heterocyclic diamine with various commercially available aromatic dianhydrides via the conventional two-step method. These obtained PIs were investigated in aspects of their solubility, thermal, mechanical, and optical properties for studying the effects of the heteroaromatic rings into the main chain. At the same time, the impact of the two isomers introduced into the PI was discussed in detail.

Novel soluble polyimides containing pyridine and fluorinated units: preparation, characterization, and optical and dielectric properties

To acquire low dielectric constant polyimide films with good mechanical and thermal properties and low CTE applied in microelectronic fields, three novel polyimides containing pyridine and –C(CF₃)₂– groups were firstly designed and synthesized.

Organosoluble and high Tgpolyimides from asymmetric diamines containing N-amino and N-aminophenyl naphthalimide moieties

Two series of polyimides derived from two asymmetric diamines are synthesised by different polymerization methods. The effect of asymmetry and non-coplanarity of two bisimides on the polymer properties is well investigated.

Synthesis and crosslinking study of isomeric poly(thioether ether imide)s containing pendant nitrile and terminal phthalonitrile groups

Upon crosslinking, phthalonitrile-terminated polyimide PN-PI (a–d) films exhibited better solvent resistance, and greater thermal and mechanical properties than PI (a–d) films.