Synthetic routes to responsive polymers; co-polycondensation of tri-functional amino acids with diacylchlorides

The condensation of diamino acids and their derivatives such as L-lysine, L-lysine ethyl ester and L-ornithine with aromatic and aliphatic diacyl chlorides was investigated. Linear polyamides bearing carboxylic acid or ester functional groups pendant to the backbone with reasonable molecular weight (M-w 56-66 kDa) could be produced using either a single phase aqueous acetone solution method or a bi-phasic carbon tetrachloride/aqueous method. The effect of reaction conditions on product yield and molecular weight were also investigated. The molecular weight averages of polymers produced using a single phase aqueous acetone solution method were found to be comparable to those of similar polymers synthesized using interfacial polycondensation. In addition, esterified and non-esterified diamino acids could be copolymerised using the single phase technique whereas two distinct products were obtained when a bi-phasic method was used. (C) 1999 Elsevier Science B.V. All rights reserved.