Formation of Mg₃Si₂O₅(OH)₄Nanotubes under Hydrothermal Conditions

Effects of nanofiller morphology and aspect ratio on the rheo-mechanical properties of polyimide nanocomposites

“…Silicate nanotubes (SNT) with a chrysotile type structure of Mg 3 Si 2 O 5 (OH) 4 were synthesized using a hydrothermal method that is facilitated by high pressure autoclaves as described elsewhere [7]. The SNT density is 2.5 g/cm 3 .…”

“…Therefore, there is a need to develop synthetic nanofillers with prescribed particle composition, shape and size for use as fillers in polymer nanocomposites with well defined properties. In this area, synthetic nano-dimensional silicates may provide a number of opportunities in polymer nanocomposites that is relatively little studied and poorly understood relative to the well studied polymer nanocomposites filled with natural layered MMTs [5][6][7][8][9]. In contrast to the commonly used layered MMT compounds, it is envisaged that use of nanoparticles with different morphology (e.g., nanotubes and nanoparticles of isometric shape) might provide additional benefits in polymer nanocomposites not possible with MMT.…”

“…In contrast to the commonly used layered MMT compounds, it is envisaged that use of nanoparticles with different morphology (e.g., nanotubes and nanoparticles of isometric shape) might provide additional benefits in polymer nanocomposites not possible with MMT. Suitable techniques for hydrothermal synthesis of silicate nanotubes and particles of isometric form (e.g., zirconium dioxide) that gives the possibility to control the resulting nanoparticle's structure by varying the mode of hydrothermal synthesis has been reported [7][8][9]. Polyimide (PI)-based nanocomposites are of special interest because of the well known excellent heat resistance, chemical stability, and superior electric properties of polyimides [10].…”

“…It is well known that it is very difficult to find thermally stable modifier to improve clay compatibility with high temperature polymers such as polyimides that must be processed at elevated temperatures as already mentioned. The work presented herein is focused on investigating the feasibility of using as nanofillers for polyimide matrices new silicate type nanotubes (SNT) and zirconium dioxide (ZrO 2 ) nanoparticles (with different morphology as compared to layered MMT platelets) that were custom synthesized specifically for nanocomposite application [7,8]. The rheology and mechanical behavior of the PI nanocomposites as a function of the nanofiller shapes (i.e., platelets, nanotubes and isometric form) will be presented and discussed to provide a starting point for further experiments that will improve our understanding of optimal methods of incorporating nanoparticles with varying shapes and sizes into polyimide matrices and of the effects of the nanoparticles morphology on the structure and properties of polyimide nanocomposites in general.…”

Polyamide-Imide Membranes of Various Morphology - Features of Nano-Scale Elements of Structure

“…These NT were produced by hydrothermal treatment of various precursors: magnesium oxide, silicon dioxide, and MgSiO 3 with NaOH solutions at NaOH concentration of up to 3 wt % at temperatures of (250 -450) C and pressures of 30-100 MPa by the procedure described in [41,42]. Nanotubes of composition Mg 3 Si 2 O 5 (OH) 4 were used, with a cylindrical morphology and following dimensions: outer diameter d o = 20-25 nm, inner diameter d i = 4 nm, and length L = 500 -1000 nm (NT).…”