Preparation and characterization of PAMAM dendrimer polycondensates

A novel class of three-dimensional polycondensates were prepared with PAMAM dendrimers having terminal multi-functional groups and other compounds, on the basis of polycondensation mechanism. The X-ray electron spectrometer (XPS) was resorted to analyze the polycondensates, and the fit data of carbon element value in Electron Spectroscopy for Chemical Analysis (ESCA) was utilized to estimate the extent of polycondensation. The fit peaks of carbon of ester groups (-COO-) were almost disappeared and they might reacted with amido and formed acylamide (-CON), therefore the polycondensation reactions were almost completely. The swelling tests of polycondensates were carried out in the hexane, toluene, chloroform, isopropanal, acetic acid, ethanol, formic acid and water. It was found that the max swelling value reached in the formic acid. Hence the solubility parameter of polycondensates (δ₂) was about 27.6 (MJ/m³)^1/2 (as the same as formic acid) according to the meaning of δ₂. The DSC analysis of the raw PAMAM dendrimer and the polycondensates demonstrated that the glass-transition temperature (T_g) of polycondensates had been great improved, which from subzero temperature of raw materials to 48°C.