Bio-based foams with low density and thermal conductivity through ethyl cellulose and SiO2 stabilized Pickering emulsion templating

Plastic pollution represents a pressing environmental issue, with conventional plastic foams exacerbating visual pollution, soil contamination, and the accumulation of microplastics. This study focused on the preparation of fully bio-based foams as a sustainable alternative to petroleum-based counterparts using the emulsion templating method (ETM), employing 4 wt% ethyl cellulose (EC) and 0.6 wt% silicon dioxide (SiO 2 ) to stabilize water-in-oil (W/O) Pickering emulsions. The curing conditions were optimized through orthogonal experiments, revealing that the optimal parameters included curing at 80 °C for 3 h with 3 % benzoyl peroxide (BPO). The foaming experiments confirmed that heating 1.0 wt% NH 4 HCO 3 as a blowing agent for 15 min facilitated the formation of porous structures. Determination of apparent density and thermal conductivity of foams, revealed that the foam exhibited a low density (0.176 ± 0.006 g/cm 3 ) and efficient thermal insulation properties (0.065 ± 0.002 W/m·K). This study demonstrated that W/O Pickering emulsion formulated with EC, SiO 2 and soybean oil epoxidized acrylate (AESO) could be effectively employed in the production of bio-based foam via ETM, thus providing a viable and environmentally friendly alternative to conventional plastic foams.