Recovery of unsaturated polyester resin into oligomer for preparation of oil-water separation aerogel

The accumulation of plastic waste has become a serious environmental pollution problem. To achieve the sustainable use of energy and the conservation of resources, it is an effective solution to convert plastics into valuable chemicals. In this work, the water-soluble oligomer of unsaturated polyester resins (LMUPR) was obtained by cleavage of the ester bonds from unsaturated polyester resins. The degradation was carried out by the one-pot method in n-butanol at 80°C for 1 h with potassium hydroxide acting as a catalyst. The LMUPR can be separated by centrifugation with a yield of 98%. The LMUPR was integrated with carboxylated chitosan and N, N-Methylene-Bis-Acrylamide to form aerogels via freeze drying. The hydrophobic oleophilic aerogel (water contact angle is 131°) was prepared by surface coating of waste polyethylene solution, which can selectively adsorb a variety of oils and organic solvents in water, and showed good adsorption capacity and cycle performance. In addition, due to the retention of the properties of unsaturated polyester resins, it shows good acid and alkali resistance and compression resistance (compressive strength 310.5 kPa). This work provides new raw materials for the synthesis of aerogels and a strategy for converting waste plastics into high-value-added adsorption materials.