Synthesis of epoxy‐ended hyperbranched polyesters with reinforcing and toughening function for diglycidyl ether of bisphenol‐A

• Published in: Polymer composites 2018-12, Vol.39 (S4), p.E2046-E2055
• Main Authors: Wang, Luping, Liang, Yeyun, Yu, Qian, Chen, Sufang, Zhang, Junheng, Miao, Menghe, Zhang, Daohong
• Format: Article
• Language: English
• Subjects: Bisphenol A; Epoxy resins; Glass transition temperature; Molecular structure; Molecular weight; NMR; Nuclear magnetic resonance; Organic chemistry; Polyester resins; Polyesters; Polymer matrix composites; Polymers; Synthesis; Temperature; Toughening
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.24443

Hyperbranched epoxy resins are excellent materials for toughening and reinforcing diglycidyl ether of bisphenol‐A (DGEBA), but the glass transition temperature usually decrease sharply. Here we report synthesis of novel epoxy‐ended hyperbranched polyesters (HEHP‐n, n = 1, 2, 3, and 4) with different molecular weights. Chemical structure of the HEHP‐n and intermediates were characterized by FT‐IR and 1H NMR. The HEHP‐n has shown remarkable effect for toughening and reinforcing DGEBA. The mechanical strength of the HEHP‐n/DGEBA composites first increased and then decreased as the molecular weight and content of HEHP‐n increased. When the composites contain 12 wt% HEHP‐3, the impact, flexural and tensile strengths of the cured HEHP‐n/DGEBA composites reached 48.0 kJ/m2, 41.2 MPa, and 74.8 MPa, respectively, which are 223.6%, 73.0%, and 46.1% higher than those of the cured DGEBA. The glass transition temperature of the cured HEHP‐n/DGEBA also increased in comparison with that of the epoxy‐ended hyperbranched polyesters/DGEBA composites reported previously. POLYM. COMPOS., 39:E2046–E2055, 2018. © 2017 Society of Plastics Engineers