Efficient Toughening of DGEBA with a Bio-Based Protocatechuic Acid Derivative

Xinxin Fang; Xin Guo; Weilin Tang; Qun Gu; Yue Wu; Hua Sun; Junfei Gao

doi:10.1021/acsomega.2c07140

Efficient Toughening of DGEBA with a Bio-Based Protocatechuic Acid Derivative

ACS Omega. 2023 Mar 10;8(11):9962-9968. doi: 10.1021/acsomega.2c07140. eCollection 2023 Mar 21.

Authors

Xinxin Fang¹, Xin Guo², Weilin Tang², Qun Gu², Yue Wu², Hua Sun¹, Junfei Gao²

Affiliations

¹ College of Biotechnology, Tianjin University of Science and Technology, 13 St. 29, TEDA, Tianjin 300457, P. R. China.
² Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, P. R. China.

Abstract

In this work, a bio-based epoxy resin, protocatechuic acid diester epoxy resin, (PDEP), was synthesized using protocatechuic acid. The structure and properties of PDEP have been characterized by ¹H NMR, ¹³C NMR, and Fourier transform infrared. After different contents of PDEP were added to diglycidyl ether of bisphenol A (DGEBA), the modified epoxy resins were cured by 4,4'-diaminodiphenylmethane (DDM). With the addition of a flexible long-chain bio-based monomer to improve toughness, the impact strength was 50 kJ·m^-2 with only 5.0 wt % PDEP; compared with pure DGEBA, the impact strength was 27 kJ·m^-2. Further, an increase in T _g should be confirmed from the mechanical cross-linking density and rigidity group content. The single T _g proved the homogeneous phase structure of the PDEP-cured resin. Morphology exhibiting the ductile fracture of the cured resin was confirmed by scanning electron microscopy. Overall, this work demonstrates the utilization of renewable protocatechuic acid as an effective modifier for epoxy resin, which reflects its potential application.