Dielectric behaviours of bio‐derived epoxy resins from cashew nutshell liquid

Abstract

In this study, four commercially available bio‐derived epoxy systems (extracted from cashew nutshell liquid) were prepared and characterised. The glass transition temperature (T g), dielectric spectroscopy, DC conductivity and breakdown properties of these epoxy resins were studied. Differential scanning calorimetry (DSC) demonstrated that the T g of the investigated systems ranged from 67 to 122°C. The DC conductivity was very low (<10−16 S cm−1) and comparable to the conventional dielectrics at room temperature (RT). However, all systems showed a strong temperature dependence of the electrical conductivity and exhibited sharp increase around their respective T g. Arrhenius analysis led to activation energy, E a, values around 1 eV; higher E a values were observed in systems with a lower T g. Dielectric spectroscopy revealed a flat and low response at temperature below T g. However, both the real and imaginary permittivity increased with decreasing frequency at mid to low frequencies as the temperatures approached T g. The variations of AC breakdown strength of all samples were not statistically significant, but the DC breakdown strength of sample 2503A + 2002B was higher than the others, which might be due to reduced charge transport in this system. The results indicate that novel bio‐derived epoxy systems from renewable sources are potential alternatives for traditional petroleum‐based epoxy systems in certain insulation applications.

Physical and dynamic mechanical properties of continuous bamboo reinforcement/bio-based epoxy composites

“…On the second run the event detected is an endothermic second-order transition characteristic of the glass transition of epoxy. The T g of pristine epoxy 92 °C , agrees with the value reported by Mu et al [45]. This value is of 93 °C and 92 °C for bamboo fibres/epoxy composites and bamboo strips/epoxy respectively.…”

Cashew nut shell oil as a potential feedstock for biodiesel production: An overview

“…CNSO is composed primarily of the chemical molecules anacardic acid, cardanol, cardol, and 2-methylcardol. Natural CNSO, also known as nCNSO, is obtained by distillation at low temperatures, whereas technical CNSO, also known as tCNSO, is obtained by distillation at high temperatures (Mu & Vaughan, 2020). Anacardic acid accounts for 70% of nCNSO, whereas cardol accounts for 18%, cardanol accounts for 5%, and the remaining 30% is made up of a variety of phenols and less polar chemicals.…”

Statistical and Artificial Neural Network Coupled Technique for Prediction of Tribo-Performance in Amine-Cured Bio-Based Epoxy/MMT Nanocomposites

“…The Formulite TM series of bio-based epoxies is one such bio-based polymer that several researchers have explored in recent times for its applicability in various engineering sectors. It is derived from natural phenolic materials that are obtained by distilling Cashew nutshell liquids (CNSL) [30][31][32][33][34]. The mechanical strength and water absorption tests conducted on the Formulite TM bio-based epoxy variants showed that they-and particularly the one comprising a combination of Formulite TM 2501A + Formulite TM 2401B-proved to exhibit properties nearing the traditionally used LY556/HY951 synthetic epoxies [35].…”