HYDROGELS BASED ON GRAFT-COPOLYMERIZATION OF 2-HYDROXYPROPYL METHACRYLATE ACRYLATE MIXTURES ON AMYLOSE - SWELLING BEHAVIOR

Hydrogels were prepared by simultaneous graft copolymerization on amyl ose of 2-hydroxypropyl methacrylate with different acrylates (methyl a crylate, ethyl acrylate and butyl acrylate) using eerie ammonium nitra te as initiator. Similarly, another series of grafted samples with a 5 0/50 (mol/mol) composition of hydroxylic/non-hydroxylic monomers with 34 mol% of ethylene glycol dimethacrylate were prepared. Percentages o f crude grafting (%CG), polymerized monomer (%PM) as well as equilibri um water content (%EWC) were analysed as a function of the monomer com position in the initial mixture and the degree of crosslinking. As the proportion of hydroxylic monomer in the copolymers increased, a sligh t rise in %EWC was observed and a higher increase as the alkyl side-gr oup length of acrylates decreased. The swelling behaviour had only an appreciable variation at basic pH, even achieving similar values to th ose of amylose when diethylene glycol dimethacrylate was added.