Inverse-suspension production of hydrogels : kinetic modeling and product characterization

Hydrogels find important applications in drug and gene delivery, tissue engineering, bio-separations and different fields of biomedicine.1 End-use properties of such polymer networks are dependent on their structural topology which is affected by the production process used. Formation of non-ideal networks due to reduced reactivity of pendant double bonds and/or cyclization are some mechanisms hindering the prediction of physical properties of hydrogels from their synthesis conditions, which is an important open problem in this research field. This work reports the synthesis/characterization of different classes of hydrogels and also the kinetic modeling of their formation process. Time evolution in batch reactor of key properties of the gelation process was measured, namely monomer conversion, weight fraction of gel, molecular weights and average radius of gyration of the soluble phase. The performance of the resulting hydrogels was also assessed (e.g. swelling ratio in different environmental conditions) in order to link the synthesis conditions with the end-use properties of such materials. A general kinetic approach is used to predict the dynamics of hydrogel formation. Comparison between experimental measurements and these predictions allows the build-up of a computational tool useful in the design of processes for production of tailored hydrogels.Financial support by Fundação para a Ciência e a Tecnologia (FCT), Ministry of Science and Technology of Portugal (Program COMPETE - QCA III) and European Community through FEDER is gratefully acknowledged (project PTDC/EQU-EQU/098150/2008