The Synthesis Of Silsesquioxanes And Their Applications In Polymerization

In this paper, a kind of partial cage polyhedral oligomeric silsesquioxanes (POSS) , [PhSi(O)OH]₄(T4), has been synthesized and characterized. T4 has been used to prepare the silicone based rare earth compound to initiate the ring-opening polymerization of ε -Caprolactone for the first time. We have studied the effects of [CL]/[Nd], n-butanol, temperature, time, polarity of the solvent on polymerization, discovering that the polymerization temperature is ranging from -20℃ 70℃ and somewhat living polymerization characters as well. The polymerization mechanism is "coordinate-insert" confirmed by the ¹H-NMR analysis of the end-group of the PCL terminated by isopropanol. We also explored the appropriate conditions for ε -Caprolactone ring-opening polymerization using the catalyst are: [Nd]=0.144mol/L in the catalyst solution, [CL]/[Nd]=1000(molar ratio), 18℃, bulk polymerization, 1h, and PCL with 92% conversion and about 1 × 10⁴ Mv is obtained.In addition, a series of POSS were synthesized step by step from phenyltrichlo-rosilane, such as octaphenylsilsesquioxane(OPS) , octa(nitrophenyl)silsesquioxane (ONPS) , octa(aminophenyl)silsesquioxane (OAPS), OAPS-MAC and OAPS-AA. The structures and properties of above POSS have been characterized. Their formation mechanism and possible applications also have been discussed.