The investigation of hydrophilic modification of membrane surface based on the mono-esterification between maleic anhydride and polyethylene glycol: Response surface methodology, reaction kinetics and performance analysis

In this work, the hydrophilic modified membrane of polyvinylidene fluoride (PVDF) matrix with better anti-fouling capacity was prepared via thermally induced phase separation (TIPS) method and the surface grafting of polyethylene glycol 2000 (PEG2000). Response surface methodology (RSM) was used to optimally design the best reaction conditions based on the objective of the grafting degree (GD). The results revealed that the most significant term to influence GD is reaction temperature. The rounded optimum conditions of reaction time, catalyst dosage and reaction temperature were 4 h, 0.6% and 73 °C, respectively. The investigation of kinetics indicated that the mono-esterification between styrene-co-maleic anhydride (SMA) and PEG2000 conforms to the second reaction kinetics and the activation energy (Ea) is 47.125 KJ/mol. This implied the feasibility for this solid–liquid (S-L) phase reaction, which can be attributed to the higher reactivity of MA functional group and the effectiveness of base-catalysis. Finally, the reason to improve anti-fouling capacity for the grafting membrane was explained by analyzing the filtration resistance. In a word, this work demonstrated the feasibility and significance for preparing hydrophilic modification membrane via the “physical blending-base catalysis grafting” method and provided a theoretical support for improving anti-fouling capacity of membrane.