Manufacturing Low Dielectric Polysaccharide Esters with High Thermal Stability

We aimed to produce biomass-based plastics derived from polysaccharides for use in electrical devices, such as printed circuit boards (PCBs). We systematically investigated the combination of polysaccharides and side chain structures to achieve specific properties, notably a high glass transition temperature (Tg), for processes like soldering, and a low dielectric constant (Dk) to minimize electrical transmission loss. Three polysaccharides were selected as backbone structures: cellulose (β-1,4-glucan), paramylon (β-1,3-glucan), and α-1,3-glucan. Three types of side chain structures were then introduced: linear, branched, and cyclic, leading to 40 derivatives. Among them, α-1,3-glucan with cyclohexane carboxylate side chains exhibited the most promising properties combining high Tg: 205 °C and low Dk: 2.7. Additionally, improving the crystallinity resulted in a further reduction of Dk to 2.5. The high Tg and low Dk properties were comparable to, or surpassed, those of conventional polymers used in PCBs, such as epoxy and polyimide (>200 °C, 3–4). Polysaccharide esters are therefore another viable option as insulating polymers in electrical devices.