High toughness plant oil-based epoxy resins simultaneous with low dielectric properties

Developing novel multifunctional polymeric materials from biomass to replace traditional electric encapsulation materials such as epoxy resins and polydimethylsiloxane is of great significance for energy consumption and sustainable development. Here, a series of bio-based epoxy thermosets were prepared using a solvent-free ring-opening polymerization-initiated process from different epoxidized plant oils. Key factors such as reactive sites and optimized curing conditions for this system were studied systematically. Moreover, the relative properties of the resulting products, including thermal, mechanical, and dielectric performance were investigated and discussed deeply in correlation with their structure and reactivity. The findings in this work demonstrated that the adjustable chain stiffness and cross-link density of cured networks, achieved through the use of different types of vegetable oils, allows for tailoring the comprehensive properties of these networks. Among the prepared samples, soybean oil-based thermoset exhibited superior tensile strength (7.5 ± 0.28 MPa), elongation at break (87.56 ± 4.80%), glass transition temperature (Tg) of approximately 23 °C, storage modulus of 5.84 MPa, and a dielectric constant of approximately 2.95 at 10 MHz. These properties endow soybean oil-based thermoset as a suitable candidate substrate for encapsulation materials, in comparison with commercial polydimethylsiloxane. The findings suggest that the functional materials designed in this study hold promise as alternatives to petroleum-based polymers and offer paramount potential for applications in diverse electronic device applications.