Polycondensation microwave-induced

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 a typical experiment, a monomer or its salt (2 g) in a polar high boiling solvent (1-2 ml) was irradiated under nitrogen atmosphere. The microwave assisted polycondensation proceeded rapidly and was completed within 5 min (inherent viscosity around 0.5 dL/g) for the polyamide synthesis [68] and within 2 min for the polyimides (inherent viscosity above 0.5 dL/g) [69]. The rate of polycondensation of the salt monomers under various conditions decreased in the following series the microwave induced polycondensation>solid-state thermal polymeriza-tion>high-pressure thermal polycondensation [71]. 

---