Synthesis and characterization of semiaromatic polyamides comprising benzofurobenzofuran repeating units

Abstract

Extended π-conjugated segments such as benzofurobenzofuran can be included into polyamides with high glass transition temperatures.

Semiaromatic Polyamides with Re-Entrant Chain Folding Templated by “U-Turn” Repeat Units

“…Our WAXS results hence clearly demonstrate that the acridine-based polyamides PA x Acr are semicrystalline, unlike certain other synthetic semiaromatic polyamides such as poly­(hexamethylene isophthalamide) (PA6I) that are also based on rigid kinked repeat units but are substantially amorphous. − Our findings further imply that the acridine-based repeat units serve as templates for a conformation reminiscent of “β-serpentine folds” so that the polyamides PA x Acr form layered structures with predetermined lamellar thicknesses and regular adjacent re-entrant chain folding stabilized by intermolecular hydrogen bonds, in marked contrast with conventional melt-crystallized semicrystalline aliphatic or semiaromatic polyamides.…”

Catalyst‐Free Synthesis of O‐Heteroacenes by Ladderization of Fluorinated Oligophenylenes

“…The incorporation of heteroatoms into the carbon skeleton is an excellent tool to adjust and improve the electronic properties of the compounds [5, 6] . In contrast to nitrogen‐ and sulfur‐analogues, [7–9] oxygen heterocycles, for example, containing furan's moiety, have drawn much less attention and became an object of interest only recently [10–19] …”

“…[5,6] In contrast to nitrogen-and sulfur-analogues, [7][8][9] oxygen heterocycles, for example, containing furans moiety, have drawn much less attention and became an object of interest only recently. [10][11][12][13][14][15][16][17][18][19] Among the main reasons for such a late splash of interest are synthetic difficulties connected to lability issues of furans. Meanwhile, a fusion of furan ring(s) to an all-carbon aromatic system appears to be a viable strategy for obtaining stable furan derivatives (also called ladder-type O-bridged heteroacenes [20] ).…”

The preparation of novel poly(ether-amide)s based on spiro[fluorene-9,9′-xanthene] and a polyamide/polymer-coated ZnO nanocomposite: thermal, optical, biological, and methylene blue dye adsorption attributes

“…These polymers can be used in various fields, such as biomedical, textile, and automotive, due to their mechanical and thermal resistance, durability, and high strength, as well as other favorable chemical and physical attributes. [1][2][3] Generally, the stiffness of the structure and intense interchain interactions of PAs endow them with high glass transition and melting temperatures which, in turn, leads to their limited solubility in most organic solvents and reduces their processability. 4 Many techniques have been investigated to overcome these shortcomings, including the incorporation of asymmetrical units, 5 polar constituents, 6 flexible bonds such as -SO 2 -, -O-, and -CH 2 -, 7,8 bulky pendant groups, 9,10 and trifluoromethyl (-CF 3 ) groups 11 within the parent chain.…”

“…30,31 The present study deals with the synthesis and design of a novel diamine with fluorene and xanthene rings substituted in its structure. Direct phosphorylation polycondensation of the Yamazaki procedure was utilized to prepare PA- (1)(2)(3)(4)(5). Spectral and elemental analyses were used for the characterization of monomers and PAs.…”