Preparation, Characterization and Performance Study of Poly(isobutylene-alt-maleic anhydride) [PIAM] and Polysulfone [PSf] Composite Membranes before and after Alkali Treatment

DFT Modeling of the Alternating Radical Copolymerization and Alder-Ene Reaction between Maleic Anhydride and Olefins

The free radical copolymerization of electron-acceptor and electron-donor vinyl monomers represents a particular case of sequence-controlled polymerization. The reactions of maleic anhydride (MA) or related compounds (acceptor comonomers) with α-olefins (donor comonomers) result in the formation of the alternating copolymers that have clear prospects for petrochemical and biomedical applications. However, in contrast to the well-established polymerization of acrylate monomers, these processes have not been studied theoretically using the density functional theory (DFT) calculations. In our research, we performed a comprehensive theoretical analysis of the free radical copolymerization of MA and closely related maleimide with different structural types of olefins at mpw1pw91/6-311g(d) level of the DFT. The results of our calculations clearly indicated the preference of the alternating reaction mode for the copolymerization of MA with α-olefins, isobutylene and prospective unsaturated monomers, as well as methylenealkanes. The DFT modeling of the thermally induced Alder-ene reaction between MA and olefins allowed to exclude this reaction from the scope of possible side processes at moderately high temperatures. Comparative analysis of MA and N-methylmaleimide (MMI) reactivity shown that the use of MMI instead of MA makes no sense in terms of the reaction rate and selectivity.

Preparation and Characterization of a Hydrophilic Polysulfone Membrane Using Graphene Oxide

In general, the polysulfone (PSf) membranes are popular choices for water treatment because they have high thermal stability and good chemical resistance. On the other hand, the filtration capacity of the polysulfone membrane is limited because of its low water flux and poor antifouling ability, which are caused by the low surface hydrophilicity of the membranes. In this research, blending of graphene oxide (GO) or graphene oxide-titanium dioxide (GO-TiO2) mixture into the polysulfone matrix had been carried out through the phase inversion method to enhance the hydrophilic and antifouling properties. Methods such as energy-dispersive X-ray spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle measurement were used to examine the surface properties of the prepared membranes. Experimental results have led to a conclusion that graphene oxide can be stabilized into prepared membranes, and then, by reducing the water contact angle values, the surface of these membranes becomes hydrophilic, which increases the permeability and the water flux of methylene blue from the aqueous feed solution, improving the membrane’s antifouling resistance.

Preparation, characterization and the effect of PANI coated TiO2 nanocomposites on the performance of polysulfone ultrafiltration membranes

The PANI coated TiO₂ nanotubes serve as effective additives for polysulfone membranes, for improving their properties.

Preparation and performance studies of polysulfone-sulfated nano-titania (S-TiO2) nanofiltration membranes for dye removal

Polysulfone nanofiltration membranes containing sulfated nano-titania (S-TiO₂) were fabricated, with the aim to enhance the membrane properties along with the possible rejection of Methylene Blue (MB) dye by membranes.

Preparation of antifouling polyetherimide/hydrolysed PIAM blend nanofiltration membranes for salt rejection applications

Polyetherimide/hydrolysed PIAM blend NF membranes have been prepared and characterized. The PEI/hydrolysed PIAM composition of 80 : 20 showed very good salt rejection (sodium sulphate) up to 76% with a pure water flux of 11.8 L m⁻² h⁻¹. This study provides a simple and effective approach to produce negatively charged NF membranes for water desalination applications with low energy consumption.

Evaluation of transport parameters for PVC based polyvinyl alcohol Ce(IV) phosphate composite membrane

The aim of this study was to investigate the preparation of novel membrane and the characterization of their properties. A new class of polyvinyl chloride (PVC) based polyvinyl alcohol Ce(IV) phosphate composite membrane was successfully prepared by solution casting method. The structural formation was confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and morphological studies. The thermal property was investigated by thermogravimetry analysis (TGA) method. The order of surface charge density for various electrolytes was found to be LiCl<NaCl<KCl.

Performance of PS/PIMA/PPEES Nanofiltration Membranes before and after Alkali Treatment for Filtration of CaCl2 and NaCl

Present article describes about the preparation of Nanofiltration (NF) composite membranes by a simple chemical treatment to the polymeric membrane composed of Poly (isobutylene-alt-maleic anhydride). After composition, anhydride functionality was converted to diacid functionality by hydrolysis using sodium hydroxide solution. Further, membrane was characterized by ATR-IR, DSC and SEM. Charge confirmation was done by IEC. Water uptake and contact angle analysis was carried out to study the hydrophilicity of the membrane. The performance study was carried out by using NaCl and CaCl2 solutions. Membranes were having higher charge density, which has resulted in better performance in terms of rejection of CaCl2 and NaCl solutions. The main focus of this research is to evaluate the effect of alkali treatment on Donnan and size exclusion mechanism during membrane filtration.