SURFACE SELECTIVITY IN BLENDING POLYETHYLENE POLY(ETHYLENE GLYCOL) BLOCK COOLIGOMERS INTO HIGH-DENSITY POLYETHYLENE

Functionalization of polyethylene with block cooligomers of polyethylene and poly(ethylene glycol) is described. Poly(ethylene glycol) of different molecular weights was used. The block cooligomers of polyethylene and poly(ethylene glycol) were codissolved with additive-free polyethylene and then precipitated to obtain entrapment-functionalized powders. These powders contained 0.3-15 wt % of the cooligomer in the host high-density polyethylene and contained a mixture of the block cooligomer and virgin polyethylene. Solvent casting using these powders was used to produce polymer films which were analyzed by contact angle, XPS, and ATR-IR spectroscopy. These analyses showed that the poly(ethylene glycol) units ended up primarily at the outermost layers of the film. Further, the extent of segregation of these block cooligomers to the edges of these films increased as the weight percent loading of the cooligomer decreased. Block cooligomers with large poly(ethylene glycol) groups had a greater selectivity for the surface than similar block cooligomers with smaller poly(ethylene glycol) groups.