Synthesis of novel aromatic polyamides containing both sulfone linkages and cardo groups by a recyclable palladium-catalyzed carbonylation and condensation polymerization

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 units disturbed the good packing of PA chains and reduced the packing density, thereby facilitating the penetration of solvent molecules through the polymer chains. Compared to previously reported work 6,7,12 due to the structure of spiro and xanthene, these polymers exhibited better solubility in less polar solvents. Meanwhile, the solubility of these PAs can depend on the chemical structure of the diacids used.…”

“…The lowest T 10% and CY value for PA-3 and PA-4 in this series of PAs can be explained by the flexible -CH 2 linkages in their diacid portion. In general, these compounds show more thermal stability than other polymers synthesized in recent years [5][6][7]10,11 which might be mainly attributed to their higher structural hardness due to presence of bulky loop units twisted into their main structure. In addition, Fig.…”

“…[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.…”