Membrane Materials, Spinning Technology, and Structure

Dialyzer membrane performance depends on the biomaterial used, its thickness, and the hydraulic permeability, pore size and density, biocompatibility, and the hydrophilic/ hydrophobic properties. Some of these properties are discussed below. 

Current dialyzer membranes can be classified based on their chemical compositions as (1) cellulosic, (2) modified cellulosic, and (3) synthetic. Each of these membrane types will be discussed in detail. 

3 Noncellulosic Synthetic Membranes In the dialysis field, the term synthetic membrane is used to denote all polymeric membranes that are not cellulose based. Table 19.2 lists the various synthetic membranes that are commercially available. Polymers such as polyacrylonitrile (PAN), polymethylmethacrylate (PMMA), and ethylene vinyl alcohol (EVAL) copolymer were adapted from the textile industry, while polymers such as polysulfone, polycarbonate, and polyurethane were developed as engineering plastics. Synthetic membranes with high water permeability were developed in the 1960s 

TABLE 19.1 Cellulose and Modified Cellulose Membranes Used in Hemodialyzers Today 

Membrane Substitution of OH Groups High/Low Flux Common Trade Names 

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