Synthesis and characterization of cage octa(aminopropylsilsesquioxane)

The compound of cage octa(aminopropylsilsesquioxane) (POSS‐NH2) was prepared in higher yield by the hydrolysis and polycondensation of trifunctional monomer H2NCH2CH2CH2Si(OC2H5)3 in the mixture of solvents acetonitrile and 1‐propanol, with tetraethyl ammonium hydroxide (Et4NOH) as the catalyst. The effects of various parameters influencing the reaction, such as monomer concentration, nature of solvents, and the content of catalyst, were investigated. Results showed that the better values of these reactive factors were nH2O/nXSiY3 = 8–9/1 (molar ratio), nEt4NOH/nXSiY3 = 0.0045 (molar ratio), respectively. The use of acetonitrile as a solvent favors the deposition and formation of the product. The existence of the higher boiling pointing 1‐propanol favors the higher reaction temperature, which accelerates the formation of octamer, reduces the reaction time and eventually increases the yield. The cage structure and its formula (H2NCH2CH2CH2)8Si8O12 of the synthetic compound were characterized by FTIR, MS, 1H, and 29Si NMR. TG curve of POSS‐NH2 shows that the cage‐like compound has high decomposition temperature and higher thermal residue than the theoretical values during the thermal processing.