Chitosan-based hydrogels obtained via photoinitiated click polymer IPN reaction

[Display omitted] •Novel thiol-ene photoinitiated reaction proposed for chitosan-based IPN synthesis.•The proposed reaction successfully elapsed forming the desired IPN systems.•Crosslinking degree and polymer ratio significantly influenced rheological properties.•Microstructure had as well a strong dependence on chitosan/click polymer ratio. Chitosan (CTS) is a polysaccharide with a wide variety of applications in the biomedical field, owing to its outstanding disinfectant properties, biocompatibility and biodegradability, but with limited mechanical properties. The proposed strategy to improve CTS-based hydrogel properties in this study is the formation of a semi-interpenetrating polymer network (semi-IPN). In this way, a photo-initiated radical click reaction was proposed to obtain a synthetic polymer, whose components were included in a CTS solution, resulting in the semi-IPN network after UV illumination. Different crosslinking degrees (CD) and CTS/polymer ratios were evaluated through rheological characterization, along with an assessment of both variables based on an experimental model design, obtaining that, for every CTS/polymer ratio, intermediate values of CD (8 %) offered the best rheological properties. In addition, chemical and microstructural characterization were carried out for selected hydrogels, obtaining consistent results according to rheological characterization, as the 1/1 CTS/polymer ratio with CD 8 % hydrogel displayed the most homogeneous pore size and distribution, consequently leading to the best rheological performance.