Acid-Cured Norbornylized Seed Oil Epoxides for Sustainable, Recyclable, and Reprocessable Thermosets and Composite Application

Abstract

Reprocessable and recyclable thermosets were produced from the epoxidized norbornene seed oils (soybean oil and linseed oil). The epoxides were copolymerized using disulfidebased aromatic carboxylic acid to mold thermosets and composites. Both the neat and reprocessed thermosets were characterized for cross-linking efficiency by dynamic mechanical analysis (DMA), Soxhlet extraction, and swelling tests; for thermal stability by thermogravimetric analysis (TGA); and for T g by differential scanning calorimetry (DSC). Mechanical properties of the thermosets were also investigated. Further, carbonized biomass sorghum fillers were added into the system to assess their effect on the final properties. Increased bio-based content, cost, and weight savings were introduced into the system by virtue of biomass filler addition. Lastly, glass-fiber-reinforced composites were molded, and their mechanical and thermal properties were evaluated using an impact tester and a universal testing machine (UTM) and by DMA and TGA, respectively. It was noticed that higher seed oil functionalization resulted in higher the reactivity and final performance properties like cross-linking density, thermal stability, and tensile modulus. Nonfilled epoxy systems in comparison to the sorghum-filled thermosets and composites showed enhanced thermomechanical properties. Chemical recycling and reprocessing abilities of these highly bio-based materials were also investigated. The research thus demonstrates the systems' possible use in environmentally friendly, sustainable, and lightweight composites.

Bioplastic: an eco‐friendly alternative to non‐biodegradable plastic

“…The use of biomass filler increases a system's biobased content, reduces costs and reduces weight, one of these organic nanofillers being cellulose. 64 The demand for fiber-reinforced composite materials is increasing because of their exceptional low weight, high weight-to-strength ratio and long-term durability properties. As a result, the next generation of biobased polyurethanes must be economical and based on nondepletable biobased resources.…”

“…These unsaturated bonds are highly desirable for this type of application as they can be chemically modified through epoxidation to increase reactivity toward further polymerization. The use of biomass filler increases a system's biobased content, reduces costs and reduces weight, one of these organic nanofillers being cellulose 64 . The demand for fiber‐reinforced composite materials is increasing because of their exceptional low weight, high weight‐to‐strength ratio and long‐term durability properties.…”

Synthesis and properties of a nonionic water-based epoxy curing agent

“…In addition, Alice Mija, [28][29][30] Jomin Thomas 31,32 et al reported the application of bio-based or vegetable oil epoxide, which could potentially compete with waterborne systems.…”

Curing and thermal degradation behavior of epoxy‐based vitrimers

“…It restricts the sustainable development and application of thermoset polymers 7,8 . In 2011, Leibler and colleagues introduced dynamic covalent bonds (ester bonds) into the cross‐linked network of fatty acid or anhydride cured epoxy resins by accelerating the exchange of esters using catalysts, so that the network can be reprocessed with constant cross‐link density, and named this material “vitrimer.” 9 Epoxy vitrimers have the potential to become a more sustainable polymer material option by demonstrating reprocessability and environmental friendliness during processing 10,11 …”

“…9 Epoxy vitrimers have the potential to become a more sustainable polymer material option by demonstrating reprocessability and environmental friendliness during processing. 10,11 The curing kinetics and investigation of epoxy resins are an important issue of composite technology research, providing guidance and theoretical basis for the manufacturing forming and processing process of composites. There are various methods to study curing kinetics, such as differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and rheological analysis.…”