Cross-Linked Polyamides Synthesized through a Michael Addition Reaction Coupled with Bulk Polycondensation

Abstract

A simple route is described to synthesize crosslinked polyamides (cPAs) with excellent mechanical properties at mild conditions through a Michael addition reaction coupled with bulk polycondensation. A Michael addition of methyl acrylate with 1,6-hexanediamine was conducted in a bulk state at a N−H/CC molar ratio of 1:1 under normal pressure at 50 °C, and a hexanediamine-tetraester was prepared. Bulk polycondensation of the hexanediaminetetraester with 1,6-hexanediamine and isophoronediamine was conducted at 170 °C for 1 h and then in tetrafluoroethylene mold under reduced pressure for another 8 h. A series of cPA films were prepared. The Michael addition and the polycondensation were monitored by Fourier transform infrared, 1 H NMR, and electrospray ionization mass spectrometry spectra. The cPA films were characterized with differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and a tensile test. These cPAs exhibited T g ranging from 37 to 61 °C, tensile strength up to 71 MPa, and strain at break of about 11%.

Synthesis and characterization of ultra‐tough crosslinked polyamide with hybrid polymer networks equipping strong hydrogen bonds

“…The bright yellow cPA with various BAHD content (0, 10, 30, and 50 mole%) was named H10, BH19, BH37, and BH55. Inspired by the previous reports, 5,8,9,13,17 the mechanical strength and toughness of cPAs highly depend on the content of the cross-linker or hard segment in the polymer system, the mechanical performances of cPAs were changed from soft elastic material to hard elastic material with the increase of cross-linker (i.e., MA or AA) or hard segment (see Table 2). In addition, the increase in hydrogen-bonding networks (i.e., amide group) in the cPAs system helped the materials exhibit tougher and stronger performance because hydrogen bond is a kind of flexible and dynamic hard segment.…”

“…Michael addition is an efficient reaction to yield C‐N bonds by ene‐amine addition, and it has a wide range of applications for the preparation of the networked polymer 5,7–11 . Especially, it can be suitable to prepare the high‐value cPA.…”

“…Michael addition is an efficient reaction to yield C-N bonds by ene-amine addition, and it has a wide range of applications for the preparation of the networked polymer. 5,[7][8][9][10][11] Especially, it can be suitable to prepare the high-value cPA. In polyamide materials using by Michael addition method, electron-deficient olefins like acrylic acid (AA), methyl acrylate (MA), or other acrylate are often selected as electron acceptors, while aliphatic amines are used as effective electron donors.…”

Catalyzed Michael addition, polycondensation, and the related performance of Diels–Alder self‐healing crosslinked polyamides

“…Thermoset polymers have a three‐dimensional cross‐linked structure, and they exhibit remarkable advantages, such as solvent resistance, heat resistance, dimensional stability, and excellent mechanical properties. [ 1–3 ] During their application period or under external force, thermosets produce macro or micro cracks. [ 4 ] Limited by their stable structure, thermoset materials are difficult to repair.…”

A novel fluorescent probe for rapid detection of sulfur dioxide in living cells

“…Compared to these classical detection methods, fluorescence imaging technology has superiority in biological researches which could serve as a powerful tool for real-time detection of ions and biomolecules in living organisms. [24] It is known that many delocalized lipophilic cationic dyes, [25][26][27][28] which have a complete positive charge are easily accumulated and absorbed by living cells. [29] Recently, although many SO 2 Abbreviations used: Cys, cysteine; DMEM, Dulbecco's modified Eagle's medium; DMSO, dimethylsulfoxide; ESI, electrospray ionization; HPLC, high-performance liquid chromatography; HR-MS, high resolution mass spectrascopy; FIA, flow injection analysis; NMR, nuclear magnetic resonance; PBS, phosphate-buffered saline; SD, standard deviation; SO 2 , sulfur dioxide; TBHP, tert-Butyl hydroperoxide; TLC, thin layer chromatography; UV, ultraviolet.…”