Monitoring the structure–reactivity relationship in epoxidized perilla and safflower oil thermosetting resins

Abstract

The reactivity of epoxidized perilla oil and epoxidized safflower oil with two aromatic dicarboxylic acids was studied. The presence of S–S bonding at the β position of the carboxylic group increases the reactivity of the acidic proton toward epoxy ring opening.

Influence of the Presence of Disulphide Bonds in Aromatic or Aliphatic Dicarboxylic Acid Hardeners Used to Produce Reprocessable Epoxidized Thermosets

“…In this series, the DTBA showed again the lowest activation energy, ~77.65 kJ·mol −1 . This result corroborates well with our previous kinetic investigation for ELO with DTBA and DPA [ 28 ]. A higher E a was obtained for the formulation with the DPA hardener, so not containing the disulphide linkage, ~81.65 kJ·mol −1 .…”

“…Using both methods, the lowest values of E a were obtained for EPLO, 76.72 and 83.65 kJ·mol −1 , confirming again that this EVO has the highest reactivity ( Table 2 ). Recently, we calculated the E a applying in situ FT-IR analysis during the curing of EVOs with DTBA and DPA and also reported by this method that EPLO is the most reactive monomer, with a lower E a value, as a consequence of its high epoxy content [ 28 ]. The ESFO/DTBA system shows the highest E a values, 79.23 and 86.37 kJ·mol − 1 ( Table 2 ), in good agreement with the previous DSC results related to the enthalpy of this reaction.…”

“…A higher E a was obtained for the formulation with the DPA hardener, so not containing the disulphide linkage, ~81.65 kJ·mol −1 . We explained that the presence of dynamic S–S bonds in the β position of the carboxylic group increases the reactivity of the acidic proton toward the epoxy groups, and therefore produce an increase in reactivity [ 28 ]. In addition, the comparison between aromatic vs. aliphatic hardener (ELO/DTBA vs. ELO/DTDA) exhibited the lowest reactivity for the aliphatic hardener, with, respectively, 77.65 vs. 108.53 kJ·mol −1 .…”

New Impedimetric Sandwich Immunosensor for Ultrasensitive and Highly Specific Detection of Spike Receptor Binding Domain Protein of SARS-CoV-2

“…41 The peak at 2927 cm −1 can be assigned to the C−H stretching. 42 The strong peak at 1726 cm −1 was referred to the carbonyl group (CO) in the repeating unit of the polymer. 43,44 FTIR spectroscopy is a well-known analytical method to characterize the samples with biological origins.…”

Kinetical Study, Thermo-Mechanical Characteristics and Recyclability of Epoxidized Camelina Oil Cured with Antagonist Structure (Aliphatic/Aromatic) or Functionality (Acid/Amine) Hardeners

“…Rekondo et al [ 8 ] synthesized a polyurethane elastomer using an aromatic diamine disulfide crosslinker, 4-aminophenyl disulfide (4-AFD), and showed that self-healing occurred at room temperature with a repairing efficiency of more than 95%. Zeng et al [ 9 ] obtained a reprocessable castor oil-based polyurethane by incorporating 4-AFD and reported [ 10 , 11 , 12 , 13 , 14 ] that the mechanical properties were completely recovered after reprocessing. For the first time, our team produced reprocessable, repairable and recyclable epoxidized vegetable oil (EVO) thermosets by using 2,2′-dithiodibenzoic acid (DTBA) as a crosslinker.…”