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

Abstract

In an attempt to prepare sustainable epoxy thermosets, this study introduces for the first time the idea to use antagonist structures (aromatic/aliphatic) or functionalities (acid/amine) as hardeners to produce reprocessable resins based on epoxidized camelina oil (ECMO). Two kinds of mixtures were tested: one combines aromatic/aliphatic dicarboxylic acids: 2,2′-dithiodibenzoic acid (DTBA) and 3,3′-dithiodipropionic acid (DTDA); another is the combination of two aromatic structures with acid/amine functionality: DTBA and 4-aminophenyl disulfide (4-AFD). DSC and FT-IR analyses were used as methods to analyze the curing reaction of ECMO with the hardeners. It was found that the thermosets obtained with the dual crosslinked mechanism needed reduced curing temperatures and reprocessing protocols compared to the individual crosslinked thermosets. Thanks to the contribution of disulfide bonds in the network topology, the obtained thermosets showed recycling ability. The final thermomechanical properties of the virgin and mechanical reprocessed materials were analyzed by DMA and TGA. The obtained thermosets range from elastomeric to rigid materials. As an example, the ECMO/DTBA704-AFD30 virgin or reprocessed thermosets have tan δ values reaching 82–83 °C. The study also investigates the chemical recycling and the solvent resistance of these vitrimer-like materials.

Valorization of camelina oil to biobased materials and biofuels for new industrial uses: a review

“…The authors observed interesting properties for the camelina derived alkoxy fatty acids which suggested their great potential for low temperature applications as bio-lubricant base stocks and good alternatives for synthetic and mineral oil derived lubricants. 112 In a recent report by Mauro and coworkers (2021), 119 they reported on the synthesis of reprocessable resins derived from epoxidized camelina oil when using antagonistic structures, either aromatic or aliphatic amines or acids, as hardeners. They explored two different combinations: the rst was a combination of aliphatic/aliphatic carboxylic acids (3,3 0 -dithiodipropionic acid, and 2,2 0 -dithiodibenzoic acid), while the second consisted of only aromatic structures with acid/amine functionality (4-aminophenyl disulde, and 2,2 0 -dithiodibenzoic acid).…”

“…In a recent report by Mauro and coworkers (2021), 119 they reported on the synthesis of reprocessable resins derived from epoxidized camelina oil when using antagonistic structures, either aromatic or aliphatic amines or acids, as hardeners. They explored two different combinations: the first was a combination of aliphatic/aliphatic carboxylic acids (3,3′-dithiodipropionic acid, and 2,2′-dithiodibenzoic acid), while the second consisted of only aromatic structures with acid/amine functionality (4-aminophenyl disulfide, and 2,2′-dithiodibenzoic acid).…”

Carbon Fiber/PLA Recycled Composite

“…Mechanical strength, durability, chemical, and thermal resistance, and dimensional stability are all advantages of this material. However, because processed thermoset polymers are crosslinked, recovering the fibers is challenging as they cannot be easily heated, shaped, processed, or re-crosslinked following treatment [ 37 ]. Recycling CFRP trash reduces greenhouse-gas emissions associated with CFRP waste while also providing an inexpensive option to make high-value carbon fibers.…”

Self-Healable Covalently Adaptable Networks Based on Disulfide Exchange

“…As shown in Figure 4 d, all of the samples showed an obvious rubber platform after the glass transition. We calculated the crosslinking density of each film by using the cross-linking density calculation formula: v e = E ’/3 RT [ 47 ], where E ’ represents the energy storage modulus under T g + 50 °C, R refers to the gas constant, and T is T g + 50 °C. T g is closely correlated with the cross-linking density and transferred from 30 °C to 46 °C, with T g increasing with the number of prepolymer acetoacetate groups, and lower cystamine-prepared films compared to 1,6-diaminohexane-prepared films, which is consistent with the results obtained by DSC (with the same trend as T g ).…”