Dielectric Properties of Bio-Based Diphenolate Ester Epoxies

Thermoset bio-based diglycidyl ether of diphenolate esters (DGEDP) exhibit comparable mechanical properties as petroleum-derived diglycidyl ether of bisphenol A (DGEBA), whereas DGEDP is derived from levulinic acid, a safe and readily renewable feedstock. To determine the potential replacement of DGEBA as dielectric materials, a series of DGEDP-esters (i.e., methyl, ethyl, propyl, and butyl esters) were synthesized and studied. Broadband dielectric spectroscopy revealed that DGEDP-propyl has the highest dielectric constant in the series, comparable to DGEBA. Differences in the dielectric properties of DGEDP-esters is attributed to the interplay of segmental, small local, and side-chain motions on one hand and free volume and stric hindrance on the other.