Silsesquioxane Barrier Materials

Abstract

Cubic octameric silsesquioxanes, because of their octahedral structures and nanometer size, represent potentially very useful nanoconstruction sites. Here we report the reaction of octaaminophenylsilsesquioxane (OAPS) with a variety of epoxides and dianhydrides and their subsequent heat treatment to form nanocomposite films with exceptional oxygen barrier properties. While solution-cast films give relatively low oxygen transmission rates (OTR), casting followed by warm-pressing lowers the OTR to values competitive with commercially available high-performance barrier films. The lowest OTR measured was obtained with a warm-pressed bilayer films consisting of OAPS/tetraglycidyl-m-xylenediamine and OAPS/2,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate with OTRs < 1 cm3 20 μm/(m2 day atm). These silsesquioxane films are thermally very robust, particularly the OAPS/imide films (>500 °C when fully cured), making them ideal for electronics packaging and encapsulation applications.

Thermal stability and flammability of polyurethane foams chemically reinforced with POSS

“…Apart from traditional halogenated and non-halogenated fire retardants, new alternatives are being tested, e.g., polyhedral oligomeric silsesquioxanes (POSS). They are unique nanobuilding blocks that can be used to obtain a wide variety of hybrid materials with a range specific properties [14][15][16]. POSS consist of a siliceous cage-like core with Si atoms on the vertices and O atoms on the edges.…”

Thin film composite nanfiltration membranes for extreme conditions

“…The quality of the thin coating layer depends mainly on the spinning speed [19], solvent evaporation rate [20,21], viscosity or concentration of the polymer solution [22] and the pore and surface characteristics of the support [18]. By keeping in mind these physical parameters, a thin polymer film of almost any composition can be coated on a suitable support.…”

“…These measurements were performed using an electrokinetic analyzer SurPASS (Anton Paar, Graz, Austria), using an adjustable gap cell with a procedure described elsewhere [18]. …”

“…An alternative is using oligomers, or broadly distributed mixtures thereof, combined with gas chromatography [12][13][14], total organic content analysis [15][16][17][18], gel permeation chromatography (GPC) [19][20][21][22][23][24][25][26][27] or high pressure liquid chromatography [5,28]. Polyethylene glycols (PEG) are cheap oligomers that are easily available with a molecular weight ranging from 62 g mol -1 (ethylene glycol monomer) up to ~40,000 g mol -1 .…”

“…Ultrafiltration polyacrylonitrile (PAN) membranes (type HV3), supplied by GKSS-Forschungszentrum Geesthacht GmbH (Germany), which have been reported to encompass reasonable chemical stability [17], have been used as support membranes for the IP process. The performance of the membranes has been evaluated in a pH range from 1 -13, using polyethylene glycol (PEG) [18] and glucose molecules, using a batch filtration setup. The performance has been compared to the performance of commercial nanofiltration membranes at neutral pH.…”