Synthesis and characterization of new unsymmetrical diamine monomer and polyimides

Abstract

A novel unsymmetrical monomer 5-(4-aminophenoxy)naphthalene-1-amine was prepared from 5-amino1-naphthol and 4-nitrofluorobenzene by the nucleophilic substitution reaction followed by reduction using 'Sn' and HCl. The structure of the monomer was confirmed by FT-IR and 1 H-NMR. A series of aromatic polyimides were successfully prepared from this diamine and aromatic dianhydrides through high temperature solution imidization technique. The polyimides were fully characterized by viscosity measurements, solubility test, FT-IR and 1 H-NMR spectroscopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetry. The X-ray diffraction patterns indicated that all these polyimides were amorphous. The polyimides exhibited good solubility in organic solvents. The glass transition temperature values were observed in the temperature range 210-287°C. Thermogravimetric analysis indicated that 10% weight loss occurred in the temperature range 385-463°C.

Effect of cyano dipolar groups on the performance of lithium-ion battery electrospun polyimide gel electrolyte membranes

“…where ε is the porosity of membrane, W w (g) is the mass of the wet membrane, W d (g) is the mass of the dry membrane, ρ w (g/cm 3 ) is the density of water, A (cm 2 ) is the area and δ (cm) is the thickness of the membrane.…”

“…Therefore, significant efforts have been performed to chemically modify the structure in order to improve their processability without affecting other relevant properties, such as thermal stability or mechanical properties. These modifications often rely on the introduction of flexible groups, such as-O-, -CO, -SO 2 -, -S-and -C(CF 3 ) 2 -, into the backbone of the polyimides, inclusion of bulky side groups or incorporation of a kink in the backbone through ortho or meta catenation instead of para catenation [3].…”

Synthesis, characterization, and properties of novel diol monomers and processable thermally stable polyimides

“…Many significant synthetic efforts have been made to improve the processability without compromising on the thermal stability. The most efficient methods are (i) incorporation of flexible linkages in the polyimides chain, (ii) incorporation of kinks in the polyimides chain, (iii) incorporation of large nonpolar and polar pendant groups in the polyimides chain, and (iv) attachment of flexible side chain in the polyimides chain [9][10][11][12].…”

Synthesis and characterization of novel star-branched polyimides derived from 2,2-bis[4-(2,4-diaminophenoxy)phenyl]hexafluoropropane

“…Owing to their rigid backbones and strong intermolecular interactions, most linear polyimides are usually insoluble and infusible which result in difficult processing and further limit their applications. 10,11 In recent years, tremendous efforts have been invested in developing various melt-processing or organic solvent soluble linear polyimides, which derived from novel diamine or dianhydride having one or more special functional structures, such as exible linkages, [12][13][14][15] bulky substituents, [16][17][18] uorinated 19 or sulfur 20 groups, non-coplanar and unsymmetrical structures, [21][22][23] etc. These are effective methods to overcome the above-mentioned shortcomings without sacricing their inherent excellent thermal and mechanical properties.…”