Keywords: Poly(l-lactic acid); poly(ethylene glycol); activated carbon; membrane; and polyurethane

Abstract

Poly(lactic acid) (PLA) is a bio-based polymer from plant resources and has been demonstrated to form porous, hydrophilic and strong structure when copolymerized with poly(ethylene glycol) (PEG). Thin film based on PLLA-PEG polyurethane copolymer has an interesting potential application as a disposable biodegradable water filtration membrane. This study aims to develop PLA-PEG polyurethane copolymer thin film membrane with a series of activated carbon (AC) contents of 2, 4, 6, 8, and 10 wt.%. Membrane matrix was first synthesized via chain extension reaction of dihydroxyl terminated PLLA and PEG prepolymers with hexamethylene diisocyanate, before the addition of AC, followed by membrane fabrication. Combining PLLA-PEG with AC resulted in changes in the morphology, thermal properties, and permeability of the membrane. Formation of urethane groups was observed in the ATR-FTIR spectrum based on the appearance of a new peak at 1619 cm−1 corresponding to -NH- group. FESEM analysis showed that membrane with 6% AC had more uniform pores compared to membranes with 2% and 10% AC. Permeation water flux test demonstrated that exerted pressure gave insignificant effect towards the resistance of membrane water fluxes, with the increment of AC resulted in increasing resistance. It was also found that the membrane with 2% AC had the highest total mean in permeation water flux, followed by 6% and 10% AC.