Direct polycondensation.

Abstract

This paper reviews the synthesis of condensation polymers by the direct polycondensation , First, the concept of the direct polycondensation and the molecular design of activating agents are described , then it is demonstrated that the direct polycondensation of dicarboxylic acids with aromatic diamines using these activating agents in the presence of triethylamine proceeds at room temperature to produce polyamides with high molecular weights . Second , these activating agents are used successfully for the chemoselective polyamidation ; that is , the polyamide synthesis from dicarboxylic acids and diamines containing various functional groups are prepared without special protection of acyl-sensitive groups , and for the sequential polyamidation ; the synthesis of regular polyamides from a symmetric (YccY) and a nonsymmetric (XabX) monomers . Finally , phosphorus pentoxide-methanesulfonic acid (PPMA) is shown to be a very useful dehydrating agent for the preparation of various condensation polymers , such as poly (ether-sulfone) , poly (ether-ketone) s and heterocyclic polymers .