Effects of poly (allylamine hydrochloride) as a new functionalization agent for preparation of poly vinyl alcohol/multiwalled carbon nanotubes membranes

Using a solution technique, poly (allylamine hydrochloride)-wrapped multiwalled carbon nanotubes (MWNT–PAH) incorporated poly (vinyl alcohol) (PVA) membranes were prepared. Multiwalled carbon nanotubes (MWNTs) were synthesized via the CVD method using cyclohexanol and ferrocene as the carbon precursor and catalyst, respectively. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The prepared membranes were subjected to pervaporation (PV) dehydration of isopropanol (IPA). MWNTs wrapped with PAH were well dispersed in the polymer matrix in comparison with prepared MWNTs. Degree of swelling (DS) of the prepared membranes decreased by addition of MWNT–PAH into the PVA matrix. Furthermore, PV results revealed that incorporation of modified carbon nanotubes (CNTs) into the PVA matrix increases water selectivity significantly due to rigidification of the polymer chains. The nanocomposite membrane containing 1 wt% of MWNT–PAH exhibited excellent PV properties. Permeation flux and separation factor were .229 kg/m2 h and 141.2 for the raw PVA and .207 kg/m2 h and 948.4 for the membrane prepared with 1 wt% of MWNT–PAH respectively. Separation factor decreased significantly by further addition of MWNT–PAH due to its agglomeration in the PVA matrix.