Synthesis and properties of biodegradable hydrogels by UV curing

Abstract

Hydrogels have been a branch of polymers which has been extensively researched due to favourable properties such structural integrity with high water uptake, making hydrogels good drug carriers, biodegradable hydrogels have also been used in branches such as tissue engineering and vascular grafts. Diacrylated polyethylene glycol (PEGDMA) and 2-Hydroxyethyl methacrylate (HEMA) have been mixed and crosslinked via a photopolymerisation method to synthesize a biodegradable hydrogel with the presence of free radical photoinitiator (Irgacure 651). The focus is on a shorter chain polymerisation of Tetra-ethylene glycol. Chemical kinetics of a mixture of 50/50 weight concentration of PEGDMA and HEMA were determined using a Differential Photocalorimetry (DPC) method. The subsequent mixture is then subjected to a 24h swelling test and the swelling properties of the PEGDMA/HEMA hydrogel were examined. The DPC results show a synergetic reaction between HEMA and PEGDMA to produce an increased reaction polymerisation (compared to individual reaction enthalpies) which is desirable. An increase in the temperature led to a corresponding increase in reaction rate, with analysis showing the reaction following the Arrhenius equation. Swelling ratios ranged from 15-42% for different weight percentages of PEGDMA/HEMA mixtures. The phenomenon can be explained by the difference in degree of crosslinking of mixture.