Acrylate copolymer-based super oil absorption resins: effects of steric hindrance of the monomer

This work reports the relationship between monomer composition of typical acrylate copolymers and their oil absorption behaviors, considering the steric effects of isobornyl methacrylate (IBOMA) or reactive silica nanoparticles. With a molar ratio of stearyl acrylate (SA): butyl acrylate (BA): IBOMA = 1:1.2:0.3, the random copolymers exhibited absorbency of more than 30 mL/g for benzene, xylene, and other common fuel oils. The copolymers of SA and BA synthesized in the presence of 2% reactive silica nanoparticles (R-SiO₂) showed further improvement in oil absorbency, reaching 39.5 mL/g, 43.6 mL/g, and 40.7 mL/g for benzene, xylene, and CCl₄, respectively. Compared to copolymers of SA and BA, copolymers formed using IBOMA or R-SiO₂ mainly hindered the diffusion of viscous oils such as kerosene or diesel, leading to decrease in absorption rate. All the prepared copolymers exhibited oil retention up to 99% for gasoline, kerosene, and CCl₄ after saturation of absorption, after centrifugation at 3000 rpm for 5 min, which is attractive for practical applications.