Quaternised polyamines

Polymeric cationic retarders that contain up to several hundred cationic groups per molecule have been proposed [45-47]. The early types [45,46] were described as quaternised polyamines (section 9.5) of relative molecular mass 1000-20 000, as compared with 300-500 for conventional quaternary ammonium compounds. Polyacrylamides of molecular mass 2500-780 000 have been evaluated more recently [47]. 

Polymeric coagulants, as stated earlier, are invariably highly cationic in nature, in order that they can neutralise the overall negative charge at the solid-liquid interface. They usually have molecular weights in the order of 250,000 up to 1,000,000. There are a number of different chemical types but the most common are based upon quaternised polyamines, polyDADMAC and polyethyleneimine (PEI). 

PDAFs are highly soluble in non-polar solvents, e.g. toluene, but insoluble in highly polar solvents, e.g. ethanol. Solubility in such solvents can be obtained by introduction of charged groups onto the side chain. The polycation 95 made by reduction of the polyamide 96 (prepared by Yamamoto polycondensation of the dibromomonomer) and quaternisation of the resulting polyamine 97 (Scheme 44) is soluble in ethanol, methanol, and water, but insoluble in non-polar solvents such as THF [195]. 

In order to produce a hydrophilic adsorbent from a polystyrene core it is necessary to shield the hydrophobic polymer backbone. One approach reported by Rounds et al. [15] involves electrostatic adsorption of a polyamine onto the surface of sulphonated, microparticulate polystyrene. This adsorbed layer is cross-linked into position and subsequently quaternised. The performance of this material was comparable with that of commercially available packings for the separation of biological macromolecules. The adsorption and subsequent cross-linking of a neutral, hydro-... 

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