Poly(amide)s obtained from 4-(4-((4-(4-aminophenoxy)phenyl)diphenylsilyl)phenoxy)benzenamine and dicarboxylic acids containing diphenylsilarylene units. Synthesis and characterization

Novel Polyelectrolytes Obtained by Direct Alkylation and Ion Replacement of a New Aromatic Polyamide Copolymer Bearing Pyridinyl Pendant Groups

The following work shows, for the first time, the synthesis and characterization of a new family of polyelectrolytes, along with their preliminary assessments in terms of desalin water treatment. These materials fall into the category of aromatic co-polyamides, which are obtained by the direct condensation of monomers 4,4′-oxydianiline (ODA), isophthaloyl chloride, and 3,5-diamino-N-(pyridin-4-ylmethyl)benzamide (PyMDA). Thereby, the charged nature exhibited by these materials was achieved through the quaternization of PyMDA moieties using linear iodoalkanes of different lengths (C_nI with n = 1, 2, 4, and 6). After completing the quaternization process, polyelectrolytes were subjected to a one-step anion substitution process, where iodide counterions were replaced by bis(trifluoromethane)sulfonamide entities. For all the obtained materials, solubility tests were carried out, showing that those alkylated with methyl and ethyl chains exhibit high solubility in rutinary aprotic polar solvents, while those containing n-butyl and n-hexyl units resulted in the formation of insoluble gels. Due to the above, the latest were discarded from this study early on. The structural characterization of the initial neutral co-polyamide was carried out by means of infrared spectroscopy (FT-IR), nuclear magnetic resonance (¹H, ¹³C-NMR), and size-exclusion chromatography (SEC), while the structure of methylated and ethylated polyelectrolytes was successfully confirmed through FT-IR, ¹H, ¹³C, and ¹⁹F-NMR. Additionally, the thermal behavior of these materials was analyzed in terms of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), showing thermal degradation temperatures above 300 °C and glass transition temperatures (Tg) above 200 °C, resulting in polymers with outstanding thermal properties for water treatment applications. On the other hand, through the solvent-casting method, both neutral and charged polymers were found to be easily prepared into films, exhibiting a remarkably flexibility. The mechanical properties of the films were analyzed using the traction test, from which tensile strength values ranging between 83.5 and 87.9 Mpa, along with Young’s modulus values between 2.4 and 2.5 Gpa were obtained. Moreover, through contact angle measurements and absorption analysis by immersion, polyelectrolytes showed important changes in terms of affinity against polar and polar substances (water, n-heptane, and benzene), exhibiting a higher rejection regarding the neutral polymer. Finally, as a preliminary test against the seepage of saline waters, thin polymer films (from 11.4 to 17.1 µm) were deposited on top of commercial filter discs and tested as filters of saline solutions ([NaCl] = 1000 and 2000 ppm). These tests revealed a decrease of the salt concentration in the obtained filtrates, with retention values ranging between 6.2 and 20.3%, depending on the concentration of the former solution and the polymer used.

Thermal and morphological properties of nanocomposite materials based on graphene oxide and l-leucine containing poly(benzimidazole-amide) prepared by ultrasonic irradiation

A new poly(benzimidazole-amide) (PBIA) was fabricated by polycondensation of 1,3-bis(5-amino-1H-benzimidazole-2-yl)benzene with chiral diacid under green media by using tetra-n-butylammonium bromide as a cheap commercially available molten ionic salt at 120°C. The affection of reaction time on the polymer yield and viscosity was tested and optimized for PBIA. Inherent viscosity value of the prepared PBIA under optimized conditions is 0.31dL/g. Then to acquire a uniformly dispersion of graphene oxide (GO) in the PBIA matrix, GO was prepared through strong oxidation procedure. After that, GO/PBIA nanocomposites (NCs) with different loading of GO were synthesized through solution mixing method under ultrasonic irradiation and the resulting NCs were characterized by different techniques. Through FE-SEM micrographs and TEM results of NC samples it can be found that the individual GO sheets were good dispersed in the polymer matrix. Also, the thermal properties of the obtained NCs were investigated and the obtained results illustrate high thermal stability with LOI values around 39-41%.

Synthesis and characterization of aromatic poly(ether-imide)s based on bis(4-(3,4-dicarboxyphenoxy)phenyl)-R,R-silane anhydrides (R = Me, Ph) – spontaneous formation of surface micropores from THF solutions

Poly(ether-amide)s derived from two new silylated-dianhydrides were prepared and characterized. By FE-SEM and AFM morphological studies were developed.

Silarylene-containing oligo(ether-amide)s based on bis(4-(4-amino phenoxy)phenyl)dimethylsilane. Effect of the dicarboxylic acid structure on some properties

Inherent viscosity and MALDI-TOF analyses suggest the formation of oligomeric chains with sequences A–B, (A–B)₂ and (A–B)₃. The properties and therefore the eventual applications of these materials are modulated by the flexibility and the aromatic content of the chains.

Silicon-containing poly(esters) with halogenated bulky side groups. Synthesis, characterization and thermal studies

Synthesis of poly(esters) X-PE-(a-c) and poly(esters) X-PE.