Preparation of a novel microporous membrane by selective dissolution of polyurethane/polyvinyl acetate polymer blend membrane

Microporous poly (urethane) (PU) membranes were prepared by solvent-casting-leaching method. PU was synthesized by two step polymerization from toluene diisocyanate (TDI), poly (propylene glycol) (PPG) and 1, 4-butanediol (BDO). Fourier transform infrared (FTIR) spectroscopy was used to verify the chemical structure of the resulting polymer. Blend membranes with a thickness of 100Âμ were prepared from the solution of PU and PVAc in chloroform by a solution-evaporation method. The amount of PVAc was varied among 10 and 30 percent by weight of the membrane. Scanning Electron Microscopy (SEM) was used to investigate the morphology of the prepared membranes. Based on the results of SEM analysis, samples containing 10% by weight of PVAc were used to prepare the microporous membranes. PVAc of the blend membrane was hydrolyzed to poly (vinyl alcohol) (PVA) and this was confirmed by 1HNMR and X-Ray Diffraction (XRD). Porous structure of the film was then formed by leaching out the PVA component from the films, using deionized water. The morphology of the porous membrane resulting from extraction of PVA was investigated using SEM. The results showed that the pores formed were spherical and had nearly identical sizes in the micron range.