Hydrogels from 2‐hydroxyethyl methacrylate and propylene glycol monoacrylate

Abstract

Hydrophilic three‐dimensional polymer networks (hydrogels) were prepared from 2‐hydroxyethyl methacrylate (HEMA) and propylene glycol monacrylate (PGMA). By wet crosslinking, hydrogels which maintain their original shape and volume relatively well, compared with the dry‐cross‐linked polymer networks, were obtained. The maximum amount of water which can be maintained in transparent hydrogels depends on the hydrophilicity of the monomers, e. g., about 40% for HEMA gels, about 50% for PGMA gels, and 40–50% for HEMA–PGMA copolymer gels depending on the monomer composition. When the water content exceeds this maximum in transparent gels (homogeneous hydrogels), they become opaque and/or spongy (heterogeneous hydrogels). Effects of the amount of crosslinking agent and the initial dilution of the monomer solution upon the swelling behavior of hydrogels were investigated. The temperature dependence of the swelling of these hydrogels and the water permeation through them were also studied.