Preparation of Bridged Polysilsesquioxane Membranes from Bis[3-(triethoxysilyl)propyl]amine for Water Desalination

Abstract

Bridged polysilsesquioxane membranes containing amine units were prepared from bis [3-(triethoxysilyl)propyl]amine (BTESPA) by a sol-gel process, which consisted of sol formation by hydrolysis/condensation polymerization of BTESPA under neutral conditions and calcination of cast films of the sols on sulfonated polyethersulfone support membrane. A similar treatment of BTESPA, including sol formation under acidic conditions, afforded membrane with ammonium units. Thus-obtained porous BTESPA-based membrane was subjected to reverse osmosis (RO) experiments using 2000 ppm aqueous NaCl solution to examine its water desalination properties. Maximal liquid permeance (1.2 © 10 ¹13 m 3 /m 2 ¢Pa¢s) and NaCl rejection (97%) were achieved using the ammoniumcontaining membrane.

Crack- and Shrinkage-Free Ethylene-Bridged Polysilsesquioxane Film Prepared by a Hydrosilylation Reaction

“…Considering these backgrounds, we reported a reverse osmosis (RO) membrane based on bridged polysilsesquioxane for water purification. 35 The rigidity of the organic bridging spacer increased the membrane pore size, and RO membranes prepared from bis(triethoxysilyl)ethane, -ethene, and -ethyne showed improved water permeability as the rigidity of the bridging units increased in the order ethane <ethene <ethyne. Bridged polysilsesquioxanes are promising materials for thermal insulation because the organic bridging spacer provides porosity and the polysilsesquioxane framework enhances the mechanical strength and the thermal property.…”

“…Bridged polysilsesquioxanes are promising materials for thermal insulation because the organic bridging spacer provides porosity and the polysilsesquioxane framework enhances the mechanical strength and the thermal property. 26,35,36 We previously reported the preparation of bridged polysilsesquioxane by the nitrogen flow method, 37 and the molecular weight of ethylene-bridged polysilsesquioxane was controlled by changing the amount of water, according to a reported procedure. 37−40 A gel film of ethylene-bridged polysilsesquioxane was obtained by heating at 80 °C for a week.…”

“…As mentioned in Introduction section, the SiCCSi ethylene bridge affords sufficient porosity to the previously reported ethylene-bridged polysilsesquioxane to be used as a membrane for water desalination. 35 Therefore, we expected it to be a good thermal insulating material because of its porosity. Unfortunately, when the ethylene-bridged polysilsesquioxane film, which was prepared by hydrolysis and polycondensation of bis(triethoxysilyl)ethane with water, was heated at 200 °C over 20 min, many cracks appeared in the film due to the shrinkage arising from the elimination of ethoxy groups.…”

Ethylene-bridged polysilsesquioxane/hollow silica particle hybrid film for thermal insulation material

“…[17][18][19] To date, we have applied bridged PSQ to reverse osmosis (RO) membrane for water purication. 20 Interestingly, water permeability was improved depending on the rigidity of the bridged spacer; namely, the membrane pore size increased by the rigidity of the bridged spacer. Based on these ndings, we have expected that bridged structure provides porosity, resulting in an excellent thermal insulator property.…”

Preparation of polysilsesquioxane reverse osmosis membranes for water desalination from tris[(ethoxysilyl)alkyl]amines by sol–gel process and interfacial polymerization

“…[6] We have been studying polysilsesquioxane (PSQ)-based RO membranes that show high mechanical and thermal stability and resistance to chlorine relative to polyamide-RO membranes. [7,8] The membranes are usually prepared by the hydrolysis/condensation polymerization of alkoxysilane precursors using the sol-gel process or interfacial polymerization. Some of the precursors for RO membrane preparation used in previous studies and the present work are shown in Scheme 1.…”