Microwave-Induced Polycondensation of Salt Monomers

Here we have combined the salt monomer method with microwave-induced polycondensation for the synthesis of aliphatic polyimides P-XPM from salt monomers XPMA and XPME (see Eq. 5, X=6-12, Ar=PM, and R=H and ethyl) [28]. When DMI or CHP was used as the solvent, the polycondensation of both salt monomers proceeded quite rapidly, and only 2 min of microwave irradiation readily afforded the aliphatic polyimides with inherent viscosities around 0.7 dL/g or above. Under these microwave irradiation conditions, salt monomers XPME were found to be more reactive than salts XPMA, judging from the attained inherent viscosity values. 

The microwave-induced polycondensation was also applied to the preparation of aliphatic polyamides. When co-amino acids and nylon salts were used as 

In short, the microwave energy was successfully applied for the first time for the rapid synthesis of condensation polymers such as polyimides and polyamides from the salt monomers (and co-amino acids) by using a simple domestic microwave oven. The rapid polymer formation is caused by the efficient internal heating of the reactants. This compares favorably with the long reaction time required for the conventional thermal polycondensation with external heating. 

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