Michael Simons. M.S., Department of Chemistry, Wright State University, 2007. Hydrophobically Modified Polyethyleneimines and Ethoxylated Polyethyleneimines. The modification of the commercially available polymers polyethyleneimines and ethoxylated polyethyleneimines took place with approximately a 3-10% alkylbromide modification followed by, in the case of the polyethyleneimines, a 2-hydroxypropyl modification, using propylene oxide, on the order of 65-70%. The objective was to increase the hydrophobicity of the polymer while keeping the cloud point above 60°C. Another approach taken was to form hydrophobic ethers from ethoxylated polyethyleneimine. We also added a 2-hydroxy ethyl group to a hexylated polyethyleneimine avoiding the use of ethylene oxide or drying EPI.