Well-defined, linear, wholly aromatic polymers with controlled content and position of pyridine moieties in macromolecules from one-pot, room temperature, metal-free step-polymerizations. Issue 38 (7th September 2020)

• Record Type: Journal Article
• Authors: Cetina-Mancilla, Enoc; Olvera, Lilian I.; Balmaseda, Jorge; Forster, Michael; Ruiz-Treviño, F. Alberto; Cárdenas, Jorge; Vivaldo-Lima, Eduardo; Zolotukhin, Mikhail G.
• Is Part Of: Polymer chemistry. Volume 11:Issue 38(2020)
• Page Start: 6194
• Page End: 6205
• Publication Date: 2020-09-07
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/d0py00946f
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : Synthesis of processable, aromatic pyridine-containing polymers has always been a great challenge. Abstract : Synthesis of processable, aromatic pyridine-containing polymers has always been a great challenge. Here, we report for the first time a robust, low-cost synthesis of well defined, high molecular weight, linear, wholly aromatic polymers with rigid ether-bond-free aryl backbones, where the proportion and position of pyridine moieties and spacer lengths between them in the macromolecules are fully controlled. The polymers, in nearly quantitative yields, were obtained by one-pot, room temperature, metal-free, non-stoichiometric superacid catalyzed step-polymerization of 4-acetylpyridine (and its mixtures with 2, 2, 2-trifluoroacetophenone) with multiring aromatic hydrocarbons: biphenyl, meta - and para -terphenyl, and para -quaterphenyl, in the mixture of trifluoromethanesulfonic acid with methylene chloride and trifluoroacetic acid. The polymers are highly soluble in most common solvents and form flexible and tough films with tensile strength in the range of 72–92 MPa. 1 H and 13 C NMR analyses of the synthesized polymers revealed high regio-selectivity of the polymer forming reaction affording linear structures with para -substitution in the phenylene fragments of the main chains. The molecular weights of the polymers ranged from 20 000 to 100 000 g mol −1, whereas the polydispersity is generally well below 2. The polymers exhibited also high thermostability with T g > 400 °C, weight loss temperatures (N2, onset) ca. 485 °C, char yields of 70–75 at 800 °C and high chemical stability. Room temperature reactions of the polymers with methyl(trifluoromethylsulfonate) afford the N -methylated cationic polymers. Certain studies on the physical properties and gas separation of the polymers are highlighted.