Water-soluble chitosan graft polymers

Researchers at Chulalongkorn University, Thailand used a one-pot-aqueous-phase process to produce water-soluble chitosan-graft-poly(ethylene glycol) methyl ether. The poly(ethylene glycol) methyl ether (mPEG) attaches to the chitosan at the amino and hydroxyl groups in a single step reaction. The mPEG reacts with chitosan and hydroxybenzotriazole in water, using a carbodiimide conjugating agent. The reaction proceeds at ambient temperature of 24 h. The water soluble product contains as much as 42% mPEG. The process does not require acids or organic solvents.