Condensation polymerisation selectivity

NCA-activated aminoacids (NCA = A-carboxyanhydride) to the lipophylic surface of palmitoyl-oleyl-phosphatidyl-choline (POPC) liposomes, has permitted the condensation of Trp-oligomers up to a polymerisation degree of eighteen, which is considerable, given that in water the synthesis by way of the same reaction is limited to oligomers of five to six due to their insolubility. The hydrophobic character of the liposome shell can also operate the chemical selection from a mixture of solutes, as illustrated qualitatively in the Figure 10.4 the most hydrophobic solute can in principle be selected out followed by selective polycondensafion. 

Offering for example enhanced heat and chemical resistance over even the best tetraphthalic polyester, there is close chemical relationship between the other two and the bisphenol-A starting point, a condensation product of phenol with acetone under acidic conditions. Then come those epoxides which, as a product of a further reaction between bisphenol and epichlorohydrin, are applicable to composites. In turn the vinyl esters can be considered as an epoxy resin backbone with terminal acrylic ester groups, dissolved in or diluted by -similar to unsaturated polyester - a monomer like styrene, which can itself be polymerised. All are chemically cured or promoted, with or without the addition of heat, although the epoxides are more selective to the use of amines for this purpose, than the other two where the peroxides are the more common. 

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