Amide-Functionalized Ionic Liquids As Curing Agents for Epoxy Resin: Preparation, Characterization, and Curing Behaviors with TDE-85

Abstract

A series of amide-functionalized ionic liquids (ILs), e.g., 1-R-3-(2-amino-2-oxoethyl)-imidazolium (R = −vinyl, −methyl–butyl) cations combined with Cl–, N­(CN)­2–, or NTf2 – anions, were synthesized and fully characterized as curing agent for diglycidyl-4,5-epoxy-cyclohexane-1,2-dicarboxylate (TDE-85). Studies of curing behaviors showed that ILs with N­(CN)2 – anions exhibit moderate curing conditions. As to thermosets of TDE-85 cured by these curing agents, their tensile strength (95.1–111.7 MPa) and elongation at break (2.69 to 4.20%) are significantly improved compared with the traditional curing systems of DDS/TDE-85 (DDS, 4,4′-diamino diphenyl sulphone). These thermosets also exhibit good thermal mechanical properties with the glass transition temperature (T g) > 200 °C and thermal degradation temperature (T d) > 300 °C. The possible mechanisms of curing reactions were analyzed by using IR, and results indicated that curing reactions of TDE-85 with amide-functionalized ionic liquids may include three steps, −NH2 groups reacted with oxirane at lower temperatures, and then the anions further participated in the reaction to strengthen the cross-linking networks. This study provides informative guidelines for designing new curing agents.

High‐performance thermosets with tailored properties derived frommulti‐armstared vanillin and carbon fiber composites

“…In this work, The DSC tests the nonisothermal curing kinetics of HPVIGEP/MeTHPA and DGEBA/MeTHPA. The Kissinger's method (Equation ) 49,50 and Ozawa's method (Equation ) 46,49,50 were the most commonly used curing kinetics model for epoxy resin systems to calculate the kinetic parameters of the curing reaction, with special the apparent activation energy(Eα). where T P is the exothermic peak temp erature, β is the heating rate, R is the gas constant (8.314 J mol −1 K −1 ), E a is the activation energy, A is the pre‐exponential factor, Figure 5 revealed the linear fitting plots based on Kissinger's equation and Ozawa's theory for the HPVIGEP/MeTHPA and DGEBA/MeTHPA systems, and the slope of the linear fitting plots can obtain the value of the E a s which concluded in Figure 5. It can be seen that HPVIGEP/MeTHPA presented lower E a than DGEBA/MeTHPA, which indicated the relatively higher curing reactivity of HPVIGEP when compared with DGEBA, using the same curing agent MeTHPA.…”

“…The corresponding curing temperatures could be confirmed as the intercept temperatures when the heating rate β was 0 C/min. 47,48 According to 46,49,50 were the most commonly used curing kinetics model for epoxy resin systems to calculate the kinetic parameters of the curing reaction, with special the apparent activation energy(Eα).…”

Imidazole derivative with an intramolecular hydrogen bond as thermal latent curing accelerator for epoxy/phenolic resins

“…Next, the mixture was poured into a preheated mold and degassed to remove bubbles. Finally, the mold was transferred to an oven, the heating procedures were conducted at gel temperature ( T gel ) for 2 h, curing temperature ( T cur ) for 2 h, and post curing temperature ( T post ) for 2 h 18 . The linear‐fit results are shown in Figure S2, and the detailed treatment parameters are listed in Table S1.…”

Synthesis and thermal degradable property of novel tertiary ester‐containing four‐functional epoxy resin

“…In this work, through molecular design, the tertiary alcohol group in linalool was used to react with isophthaloyl chloride, after double‐bond epoxidation, a new kind of four‐functional epoxy resin with weak tertiary ester linkages (FETE) was successfully prepared. Moreover, TDE‐85 (4,5‐epoxycyclohexane‐1,2‐dicarboxylic acid diglycidyl ester) epoxy resin, which had excellent thermal properties, 27,28 was introduced into FETE system to further adjust its thermal degradation behaviors.…”