Composite Membranes

The main difficulty when choosing a membrane for affinity separation of biomolecules is sometimes to find a material that fulfils several or all of the above-mentioned requirements. For example, a chemically stable material might be too hydrophobic and lead to nonspecific and irreversible adsorption of the protein to be separated, whereas a hy-drophilic material that is compatible with the fragile protein molecules might not withstand the conditions required for ligand coupling and for regeneration and sterilization of the membrane. Therefore, the choice of a membrane material will sometimes be a compromise. The use of a composite membrane consisting of two or more different materials may often be the only solution to a particular separation problem. This approach consists of the grafting of hydrophilic polymers on to a chemically and mechanically stable microporous membrane. The result is an increased biocompatibility as well as the introduction of suitable functional groups for ligand coupling. One example is the radiation-induced graft polymerization of 2-hydroxyethyl methacrylate or glycidyl methacrylate on to a polyethylene hollow fibre membrane. This increases the hydrophilicity of the material and introduces active hydroxyl groups or reactive epoxy groups.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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