Incorporation of Functionalized Silica Nanoparticles into Polymeric Films for Enhancement of Water Absorption and Water Vapor Transition

Water absorption and water vapor transition are significant mechanisms in many industrial processes. Nanocomposite polymers are appropriate materials for water transition process due to their specific properties. The present work was aimed to enhance the water absorption and water vapor transition by high loading incorporation of silica nanoparticles (NPs) into polyacrylonitrile (PAN) and Pebax 1657 polymers. PAN was used to prepare both the nanocomposite films (NCFs) and support layers of nanocomposite membranes (NCMs). Pebax 1657 was used to fabricate the selective layers of NCMs. Incorporation of NPs into the NCFs were carried out using ex-situ and in-situ (sol-gel) methods. NCFs were fabricated by electrospinning and casting methods. The fabricated NCFs of fibers and polymers were examined through water absorption tests. For fabrication of NCMs, the electrospinning and dip-coating methodologies and the incorporation of NPs into the selective layers by in-situ method were used. Besides, the water vapor permeation tests have been designed and constructed to examine the NCMs for dehydration of methane gas. In order to provide efficient NPs dispersion into NCFs, the surface functionalization of silica NPs with ethylene glycol (EG) was also considered. The functionalized silica NPs were used in the fabrication of NCFs and into the selective layer of NCMs. It is found that in applying the ex-situ method, there is a lot of NPs agglomeration, while the dispersion quality of NPs is higher with the sol-gel method. In addition, the dispersion is improved greatly with functionalization of silica NPs. The water uptake ratio of electrospun mats is about 400 % higher than the cast layers for the same loadings of NPs. The water uptake ratio of the polymeric layers containing EG is about 50 % higher than the samples without EG. The permeance of water vapor for the NCM (15 wt.% of SiO₂/Pebax 1657) fabricated by sol-gel method was enhanced to 54.4 % higher than the membranes without NPs. Functionalization of silica NPs also enhanced the water vapor permeation process. For instance, the water vapor of the NCM containing 30 wt.% of EG/Pebax1657 was increased by 68.7 %.