UV induced cross-linking of starch modified with glycidyl methacrylate

A new way to substitute cornstarch with glycidyl methacrylate (GMA) monomers is presented. This synthetic modification, carried out in DMSO, resulted in a DOS of 0.08. By exposing a water solution with modified starch and potassium persulfate (KPS), a radical initiator, to UV-Iight a free radical vinyl polymerization reaction is initiated making the starch solution chemically cross-link into a gel. The GMA modification increased the hydrophobicity of the polymer making it less water-soluble, increasing the adsorption tendency to a hydrophobic surface as seen in quartz crystal microbalance with dissipation monitoring (QCM-D) studies. The surface cross-linking process of the modified starch showed that after cross-linking the solubility of the polymer decreased resulting in a stronger adsorbed polymer to the surface compared to the non-modified starch. This proves that even though it is generally believed to be more difficult to cross-link polymers at surfaces this particular modification allowed for near complete cross-linking as suggested by the QCM-D data. (C) 2009 Elsevier Ltd. All rights reserved.