Polyurethane and sulfonated polysulfone blend ultrafiltration membranes. I. Preparation and characterization studies

Area of Science:

• Materials Science
• Polymer Chemistry
• Membrane Technology

Background:

• Ultrafiltration membranes are crucial for separation processes.
• Developing advanced membranes with tailored properties is an ongoing research area.
• Polymer blending offers a route to enhance membrane performance.

Purpose of the Study:

• To prepare and characterize ultrafiltration membranes from blends of polyurethane (ether type) and sulfonated polysulfone (sodium salt form).
• To optimize blend composition, additive concentration (polyethylene glycol 600), and phase inversion parameters.
• To investigate the relationship between membrane morphology, pore statistics, and ultrafiltration performance.

Main Methods:

• Phase inversion technique using N,N'-dimethylformamide solvent.
• Optimization of polymer blend composition and additive concentration.
• Ultrafiltration characterization (compaction, flux, water content, resistance).
• Pore statistics and molecular weight cutoff determination using dextran.
• Surface morphology analysis via scanning electron microscopy (SEM).

Main Results:

• Optimized blend membranes exhibited specific ultrafiltration characteristics.
• Polymer composition and additive concentration significantly influenced membrane properties.
• A strong interrelationship was found between pore size, porosity, pore number, molecular weight cutoff, morphology, and flux.
• SEM analysis revealed distinct surface morphologies.

Conclusions:

• Polyurethane and sulfonated polysulfone blends are suitable for ultrafiltration membrane preparation.
• The phase inversion process and blend formulation can be tuned to control membrane performance.
• Understanding the interplay between structure and performance is key for designing high-flux, selective membranes.