Study on oil adsorption/desorption kinetics and polymer network parameters of poly(lauryl methacrylate-co-hydroxyethyl methacrylate)

In the present work, oil adsorption, desorption, and resorption of poly(lauryl methacrylate-co-hydroxyethyl methacrylate) P(LMA-co-HEMA) were evaluated with different oils by a gravimetric method. Adsorption kinetics were modeled using pseudo-first-order and pseudo-second-order equations. Polymer network parameters of P(LMA-co-HEMA) regarding average molecular weight (Mc) between two crosslink piontss can be calculated by oil absorbency at equilibrium (Qe), the solubility parameter (δ) and polymer-solvent interaction parameter (χ) with Flory-Huggins relation. The results showed pseudo-second-order model has a better fit to the oil adsorption kinetic data The desorption can be analyzed by fitting a prediction of exponential-like decay to the deswelling curves. A typical oil desorption exhibited two stages: a burst release driven by concentration gradient, and a slow release controlled by diffusion and the elastic recovery of polymer networks. For reusability, the resorption behavior of P(LMA-co-HEMA) was also investigated. It was worth noting that oil resorption was faster than the first adsorption due to potential passages. Moreover, the adsorption capacity was not significantly changed after regeneration.