Euigyung Jeong  Minhui Cho  Jin-Seok Bae

Vol. 57,  No. 1, pp. 42-49, Feb.  2020
10.12772/TSE.2020.57.042

fracture tougeness Epoxy resin toughening agent toughened epoxy Click reaction

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This study analyzes the effect of novel in situ type polytriazoleketone (PTK)– toughening agent on tensile properties and fracture toughness of triglycidyl p-aminophenol (TGAP)/3,3'-diaminodiphenylsulfone (3,3'-DDS) epoxy resin. As monomers of PTK, 1,4-Bis-(azidomethyl) benzene (p-BAB) and 4.4'-bis-(propargyl-oxy) benzophenone (BPOBP) were synthesized and characterized using 1H-NMR and FT-IR analyses. The synthesized monomers were mixed with TGAP and 3,3'-DDS and polymerized to PTK during the curing reaction of the epoxy resin. By adding only 5 phr of PTK, the fracture toughness of the TGAP/3,3'-DDS epoxy resin was increased by 26.8%, whereas only 7.32% of the fracture toughness was increased by addition of 5 phr of PES. However, the fracture toughness of TGAP/3,3'-DDS decreased with the increasing amount of PTK (addition of 10 and 20 phr), whereas it significantly increased with the increasing amount of PES (addition of 10 and 20 phr). This was attributed to the poor dispersion of the solid-state BPOBP monomer in the liquid-state TGAP epoxy resin. The difference of 1.09 in the solubility between TGAP and BPOBP resulted in poorly dispersed BPOBP particles in TGAP, which resulted in a low molecular weight of the polymerized PTK during the epoxy curing reaction, and the unreacted BPOBP and p-BAB existed in the cured epoxy resin. However, PTK showed a significant improvement in the fracture toughness of TGAP/3,3'-DDS with only 5 phr, and the difference of 1.09 in the solubility between TGAP and BPOBP could be overcome with the optimized epoxy mixing procedure. Therefore, the novel in situ PTK-toughening agent can be used to improve the fracture toughness of TGAP/3,3'-DDS-based epoxy resins.