Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Neem oil was selected as a sustainable feedstock for the synthesis of an ultraviolet curable coating resin via a sequential synthetic route. Initially, neem oil was subjected to glycerolysis to produce monoglycerides, which served as reactive intermediates. The monoglycerides were then functionalized with glycidyl methacrylate, itaconic acid, and phosphoric acid, thereby incorporating polymerizable unsaturated groups and bridging moieties into the resin backbone. Upon ultraviolet irradiation in the presence of a photoinitiator, the functionalized resin underwent photopolymerization to form a polymer network. The resulting bio-based coating resin exhibited enhanced sustainability and improved performance properties.

ABSTRACT
Renewable feedstock to produce polymers as a sustainable resource has attracted considerable interest, and vegetable oils have emerged as potential bio-based feedstocks. This study reported on the utilization of Neem oil, a nonfood-grade vegetable oil, as a monomer precursor (monoglyceride) for ultraviolet-curable resin. The monoglyceride was then interacted with phosphoric acid, itaconic acid, and glycidyl methacrylate for the resin preparation. Phosphoric acid acted as a bridging agent that improved the polymer network integrity, whereas itaconic acid and glycidyl methacrylate provided unsaturated groups for polymerization. According to the results, the unsaturation double bonds were successfully polymerized by the UV curing process initiated by a photoinitiator, and the gel contents of the cured polymers were approximately 98%. The viscosity and molecular weight of the resins highly depended on the Glycerol to Neem oil ratio, as well as the content of Phosphoric acid employed. The amount of phosphoric acid also led to a decrease in the wettability of the cured films, as well as an improvement in impact resistance and adhesion strength. These results highlight the potential for Neem oil-based UV-curable coatings to act as sustainable alternatives to petroleum-derived systems and therefore pave ways toward developing environmentally friendly polymeric materials.