Development and characterization of regenerated cellulose membranes: from a biopolymer derivative to a microfiltration product

Membranes, starting from natural to industrial ones, have a fundamental role in many fields as thin barrier with characteristic permeate selectivity. For protection, separation or filtration, the membrane use increased significantly in the past century. In the last years, the possibility to obtain membranes from renewable material started to be a priority. This work focuses on the production of regenerated cellulose membranes, starting from cellulose derivative. The use of this raw material represents an important starting point in the realization of a sustainable product. Regenerated cellulose suits well filtration of aqueous solution, removal of impurities and separation treatments. The advantages of regenerated cellulose use are several: natural origin, available in large quantities, biocompatibility and biodegradability. The aim of this work is to improve an industrial manufacturing process of microfiltration membranes with required features. Particular attention is given to hydrolysis, fundamental step in order to eliminate substituent groups and maintain a stable structure. The raw materials and the competitor samples were characterized in order to realize a precise and detailed starting point for the study. Many variables were taken into consideration: the thickness of the membrane and the possibility of casting supported or not supported films.The effect of polymer concentration in the solution was studied. The influence of the solution formation temperature, the percentage of additive for pores formation and the different coagulation bath composition, have also been analyzed. Several analytical techniques were adopted in order to evaluate the previously described characteristics. The hydrolysis was conducted with a basic solution. The studies carried out have made it possible to identify a timing and a concentration suitable for the complete elimination of the substituent groups and, at the same time, for the maintenance of the membrane stability.