Influence of Mixed Solvents and Temperature on the Solution Properties of Quaternized Polysulfones

Recent advancement challenges with synthesis of biocompatible hemodialysis membranes

The focus of this study is to enhance the protein fouling resistance, hydrophilicity, biocompatibility, hemocompatibility and ability of the membranes and to reduce health complications like chronic pulmonary disease, peripheral vascular disease, cerebrovascular disease, and cardiovascular disease after dialysis, which are the great challenges in HD applications. In the current study, the PSF-based dialysis membranes are studied broadly. Significant consideration has also been provided to membrane characteristics (e.g., flowrate coefficient, solute clearance characteristic) and also on commercially available polysulfone HD membranes. PSF has gained a significant share in the development of HD membranes, and continuous improvements are being made in the process to make high flux PSF-based dialysis membranes with enhanced biocompatibility and improved protein resistance ability as the major issue in the development of membranes for HD application is biocompatibility. There has been a great increase in the demand for novel biocompatible membranes that offer the best performances during HD therapy, for example, low oxidative stress and low change ability of blood pressure.

Green Blends Based on Ionic Liquids with Improved Performance for Membrane Technology: Perspectives for Environmental Applications

Present research was directed towards the development of new high-performance and cost-effective polysulfone membranes (PSFQ) by introducing ionic liquids (ILs—Cyphos 101 IL and Aliquat 336) into their matrix. Variation of ILs was performed with the aim to find the one that brings new properties and improves the functionality and selectivity of PSFQ membranes in ultrafiltration processes. Based on the obtained results of the rheological study, we established the compatibility of compounds and optimal content of the used ILs, namely 3 wt% and 15 wt% Cyphos 101 IL and compositions varying between 3 and 15 wt % Aliquat 336. Results indicated that the ILs acted as plasticizers when they were added to the system, a helpful aspect in processing membranes used in water decontamination. The efficiency and performance of the membranes were evaluated by their use in the treatment of diclofenac (DCF)-containing waters. Membranes obtained from PSFQ/Aliquat 336 solution containing 15 wt% IL exhibited a 97% removal degree of DCF in the treatment process of 50 mL solution containing 3 mg/L DCF. The separation efficiency was kept constant for four filtration/cleaning cycles. The results indicated an improvement in membrane performance as the amount of IL in their structure increased, which confirms the potential for application in water treatment processes.

Opto-electrical properties of some quaternized polysulfones

A novel quaternized polysulfone with N-dimethylethylammonium chloride (DMEA) and N-dimethyloctylammonium chloride (DMOA) pendent groups was investigated, as to its optical and electronic properties. Optical properties were investigated by refractivity and transmission spectra. To obtain the optical parameters, the approach proposed by Tauc for amorphous semiconductors has been used, because of the similarity of the absorption edges. The values of pseudogap energy ranged between 3.60 and 3.69 eV, while those of Urbach energy were modified over the 157—172 meV range. The dielectric properties and ac-conductivity were also studied as a function of temperature, frequency and structure of pendant groups. It was observed that the dielectric constant decreased as the frequency increased and the temperature decreased. In addition, quaternized polysulfone films were characterized by two relaxation processes, i.e., γ and β relaxation, which appeared at different temperatures, depending on the pendant groups. The frequency—temperature-dependent conductivity showed that conductivity increased with frequency and also that the quaternized polysulfones possessed typical semiconducting properties. All parameters were found to be slightly influenced by the polymer chain structure.