Highly branched polyethylene used as sorbents for oil-spill cleanup and separation

Highly branched polyethylene (HBPE) was developed into practical application as highly efficient sorbent material for oil-spill cleanup and oil/water separation. To obtain large-scale production of HBPE, a thermal stable Ni(II)-alpha-diimine catalyst for ethylene polymerization in our previous work has been employed to prepare the polyolefin material in a 10-liter polymerization reactor with a high activity (>10(6) g(PE)/mol([Ni]) h). The structure, molecular weight and distribution, thermal and mechanical properties were systematically characterized by NMR, ATR-FTIR, GPC, DSC, DMA, and TGA, respectively. Through simple but feasible cross-linking process, the HBPE-based oil-absorption materials with contact angles up to 111.5 degrees were directly applied into absorption test using various oil and pure hydrocarbons. Reusability and recovery of the absorption materials and oil or solvents were probed by drying or using the distillation method. Oil/water separation was made to determine the hydrophobic and oleophilic nature of this material. Flory-Rehner polymer swelling theory is employed to study the structure-property relationship via determining the network structure including cross-linking density rho(c) and average molecular weight M-c between two cross-links. The mixture of sorbent material after absorbing oil was regarded as crude oil component to simulate oil refinery process by thermogravimetric analysis, providing an alternative approach for oil-collection.