This work reports the development of a UV-induced thiol–ene photografting process applied to cellulosic paper in a batch reactor, enabling homogeneous and controlled surface functionalization. Parametric optimisation revealed that increasing the thiol concentration from 0.05 to 0.20 mol•L⁻¹ raised the grafted sulfur content from 0.18% to 1.02%, while thiol conversion reached 98% after 90 min of irradiation at 15 mW•cm⁻². FT-IR spectra confirmed the appearance of characteristic grafting bands (C–S at 700–750 cm⁻¹, disappearance of S–H at 2550 cm⁻¹), and XPS analysis showed an S 2p doublet at 163.8 eV, indicating the formation of thioether linkages. SEM micrographs revealed no degradation of the fibre network and the presence of a uniform grafted film. The performance achieved demonstrates the strong potential of the UV thiol–ene process as a robust, energy-efficient and easily scalable strategy. Its key advantages include mild operating conditions (25–35 °C), the absence of undesired by-products, high selectivity and excellent reproducibility. This approach represents a promising route for the development of advanced cellulosic materials, opening new opportunities for applications in packaging, catalysis, functional membranes and smart surfaces.
