A Study on Swelling and Complex Formation of Acrylic Acid and Methacrylic Acid Hydrogels with Polyethylene Glycol.

Acrylic acid and methacrylic acid hydrogels were prepared by N,N -methylene bis acrylamid as a cross-linking agent in aqueous solution. The rate of swelling of prepared hydrogels in different buffers were studied and their molar mass and density of cross-linking were determined. The results indicated that at higher pHs, the acrylic acid hydrogels have higher degree of swelling than the methacrylic acid hydrogels. The complex formation between polyethylene glycol and either of acrylic and methacrylic acid hydrogels at various pHs were also studied. It was found that methacrylic acid hydrogels can form stronger complexes with polyethylen glaycol, than acrylic acid hydrogels, and the acidic pHs promote the complex formation. However the complexed hydrogels indicated lower degree of swelling.