Chemical Grafting of Polystyrene Sodium Sulfonate (PSS) onto Polyethersulfone (PES) Powder and Effect on the Characteristics of the Resultant Ultrafiltration Membranes

The quest to introduce better performing and more resilience polymeric filtration membranes is currently a topical issue. In pursuance of this, polyethersulfone-based (PES) membrane functionalized with polystyrene sodium sulfonate (PSS) were produced and assessed. In the first instance, PES powder was grafted with PSS using the benzoyl peroxide (BPO) as the radical initiator. The polymerization was carried out in a heterogeneous polymer-polymer reaction system using water as the reaction medium under inert conditions using varying amounts of PSS. The PSS grafted PES powder was characterized using a combination of FTIR and 1H-NMR spectroscopy to confirm grafting. The grafting was also confirmed through gravimetric analysis of the powder before and after the grafting reaction. The pristine PES and the series of grafted PES polymer were cast into ultrafiltration (UF) membranes via phase inversion process under similar conditions. The influence of PSSconcentration on the morphological changes, contact angle, graft yield and permeation studies was studied. The grafted PES revealed a significant change in morphology upon an increase in the PSSconcentration. An increasein hydrophilicity and pure water flux was observed to increase with the amount of PSS added to the reaction mixture.