Biobased polyhydroxyalkanoate (PHA) membranes: Structure/performances relationship

Abstract

Within the current increasing environmental restrictions, biopolymers tend to replace common materials in many applications, from daily life items to process engineering facilities. Synthetic filtration membranes are also of concern. Herein, biopolymer based microfiltration (MF) membranes were produced with a polyhydroxyalkanoate (PHA), the poly(hydoxybutyrate-co-hydroxyvalerate) (PHBHV). The membranes were made by evaporation induced phase separation (EIPS) and the influence of the dope solution composition was studied by adding additives, polyvinylpyrrolidones (PVPs) and polyethylene glycols (PEGs). The nature, molecular weight and concentration of the additives were linked to the obtained microstructures. Both types of additives can increase membrane porosity by acting as pore former agent. However, interesting opposite effects were obtained in case of PEGs from 300 to 4000 g mol−1 where the additives were observed to act as plasticizers. The membranes performances were evaluated with pure water permeability and E. coli bacteria rejection and correlated to the microstructure analyses. The performances were greatly improved by selecting the proper additive. This study leads to promising results for the consideration of PHA as new potential biomaterial intended for membrane fabrication.