A novel and green method for polycondensation reaction of 4-substituted phenylurazoles with different diisocyanates under solvent-free conditions

作者：Mallakpour Shadpour^*; Dinari Mohammad

来源：Journal of Applied Polymer Science, 2008, 108(6): 3462-3466.

DOI：10.1002/app.27851

• solid state polymerization
• polycondensation
• polyureas
• inherent viscosity
• 4-phenylurazole
• 4-(4-methoxyphenyl)urazole
• thermogravimetric analysis (TGA)
• green chemistry

In this investigation, a new method for step-growth polymerization reactions of 4-phenylurazole (PHU) and 4-(4-methoxyphenyl)urazole (MPU) with various diisocyanates were developed under solvent-free conditions. The reaction of these monomers with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and tolulyene-2,4-diisocyanate (TDI) were performed in the presence or absence of dibutyltin dilaurate (DBTDL) as a catalyst. The results of polymerization revealed that DBTDL did not have considerable effect on the polymerization process. The resulting polyureas showed good yields and moderate inherent viscosities ranging of 0.17-0.30 dL/g in NN-dimethylformamide (DMF) at 25 degrees C. They are soluble in most polar organic solvents. All of the above polymers were characterized by H-1-NMR, FTIR spectroscopy, and thermogravimetric analysis (TGA). This method was compared with the polymerization reaction in N,N-dimethylacetamide as a solvent via solution polymerization. Under solvent-free conditions, higher yields and inherent viscosities were obtained. In addition, in this method we do not need to use any solvents and the polymerization reaction can be classified as a green and environmentally friendly method.

• 出版日期2008-6-15