Highly water selective mixed matrix blend membranes of poly(vinyl alcohol)-poly(vinyl pyrolidone) incarporating phosphomolybdic acid for application in pervaporation assisted esterification of acetic acid with ethanol

摘要

Mixed matrix blend membranes of poly(vinyl alcohol)-Poly(vinyl pyrolidone)(PVA-PVP) incorporating 4 wt% phosphomolybdic acid(PMA) was prepared. The membrane was characterized by various techniques like FTIR, XRD, SEM, DSC, DMTA and Contact angle measurements. The inorganic filler phosphomolybdic acid interact with the PVA-PVP blend though hydrogen bonding between its terminal, comer and edge oxygens as evidenced by studying the FTIR spectra of both unfilled and PMA filled membranes. The comparison of XRD of the membranes showed that there is loss of crystallanity of PMA filled membrane due to the interaction between filler and the blend membrane. The uniform distribution of the PMA particles in the blend membranes was confirmed by recording its SEM. The other studies like differential scanning calorimetry and dynamic mechanical testing analysis also support the interaction between the PMA and blend membrane. The hydrophilicity of the PMA filled membrane was studied by measuring the contact angle. The enhancement of contact angle of the PMA containing membrane as compared with the prestine blend membrane indicate reduction in its hydrophilicity which increases its selectivity towards water with a decreased flux. The dynamic mechanical testing analysis of the membranes showed shifting of tan□ values to the higher temperature side indicating reduction in the polymer chain mobility due to the interaction between PMA and the polymer blend.