Degradation and recycling of cured thermosetting epoxy resins are major challenges to the industry. Here, a low-viscosity, degradable epoxy-ended hyperbranched polyester (DEHP) is synthesized by a reaction between epichlorohydrin and a carboxyl-ended hyperbranched polyester (DCHP) obtained from an esterification between citric acid and maleic anhydride. The chemical structures of DCHP and DEHP were characterized by Fourier transform infrared and H NMR. DEHP has a positive effect on reinforcing and toughening of the diglycidyl ether of bisphenol-A (DGEBA). With an increase in the content and molecular weight of DEHP, the mechanical performances of the cured DEHP/DGEBA composites, including the tensile, flexural, and impact strengths, increase first and then decrease. The improvements on the tensile, flexural, and impact strengths were 34.2-43.4%, 35.6-48.1%, and 117.9-137.8%, respectively. Moreover, the DEHP also promotes degradation of the cured DEHP/DGEBA composites. The degree of degradation of the cured DEHP/DGEBA composites increases with an increase of the DEHP content and molecular weight. The composites containing 12 wt % DEHP can be degraded completely in only about 2 h at about 90 °C, compared with the degradation degree (35%) of cured DGEBA, indicating good degradation and recycling properties of the DEHP.
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http://dx.doi.org/10.1021/acsomega.7b00132 | DOI Listing |
RSC Adv
January 2025
Packing and Packaging Materials Department, Institute of Chemical Industries Research, National Research Centre 33 El Behooth St., Dokki Giza Egypt +20 2 33371718.
Nanofiltration (NF) separation technology is a low-pressure filtration process, which is highly efficient and environmentally friendly. As a result, it has found wide application in water treatment. This work describes the preparation of flat sheet membranes the phase inversion method using blends of hyperbranched polyester amide (PEA) and polyether sulphone (PES) in definite ratios.
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January 2025
Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC 27710; Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707. Electronic address:
J Am Soc Mass Spectrom
December 2024
Department of Chemistry, University of Akron, Akron, Ohio 44325, United States.
The growing use of branched polymers in various industrial and technological applications has prompted significant interest in understanding their properties, for which accurate structure determination is vital. This work is the first instance where the macromolecular structures of dendrimers, linear polymers, and hyperbranched polymers with analogous 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) backbone groups were synthesized and analyzed via tandem mass spectrometry (MS/MS). When comparing the fragmentation pathways of these polymers, some unique and interesting patterns emerge that provide insight into the primary structures and architectures of each of these materials.
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
College of Light Industry Science and Engineering, Beijing Technology and Business University, Beijing 100048, China; China Key Laboratory of Polymer Foam Materials Processing and Application for light Industry, China. Electronic address:
ACS Appl Bio Mater
October 2024
Department of Polymer Science and Technology, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, India.
Synthetic hyperbranched polyesters with potential therapeutic properties were synthesized using the bifunctional polyethylene glycol or PEG with different molecular weights, ca., 4000, 6000, and 20,000 g/mol, and the trifunctional -aconitic acid or TAA. During polycondensation, a fixed amount of PEG was allowed to react with varying amounts of TAA (1:1 and 1:3) to control the branching extents.
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