Grafting, anionic Ionization

Membranes are films 100-200 xm thick, consisting of ionized function groups grafted on an organic polymer matrix. Snlfonic radicals are nsed for membranes permeable to cations and qna-temary ammoninm for membranes permeable to anions. 

Poly(ethylene terephthalate) (PETP) produces a relatively hydrophobic fiber that is readily soiled by oil. The soiling tendency can be eliminated by grafting 0.5 % of acrylic acid onto the fiber with the aid of ionized gases or by partial hydrolysis of the surface (whereby free —COOH groups are produced). Incorporation of 5 % adipic acid into the polymer reduces the crystallinity and thereby improves the dyeability. Incorporation of small amounts of sulfonated terephthalic acid produces anionic sites for cationic dyestuffs. 

The major forte of anionic polymerization has been the ability to prepare polydlene and polystyrene polymers and copolymers with control over the major variables affecting polymer properties. Researchers continue to exploit this method for the preparation of model block copolymers, graft copolymers, and branched copolymers, and homopolymers with controlled, well-defined structures. The ability to prepare well-defined polymers and copolymers with functionalized end groups, especially ionic or ionizable groups, is also generating considerable current interest. Methods are also being explored to anionically pol)rmerize and copolymerized a variety of polar monomers with controlled structures. The current interest in blends and... 

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