Preparation and properties of elastic polyimide‐silica composites using silanol sol from water glass

Abstract

ABSTRACT:A new approach for obtaining elastic polyimide-silica composites using a silanol sol prepared from water glass and the imide-containing elastic polymers (IEPs) with polytetramethyleneoxide (PTMO) soft-segment was investigated. Methods of increasing the degree of compatibility between the silica phase prepared from a silanol sol and IEPs obtained via elastic polyureas were examined. Elastic polyimide-silica composites were obtained by the thermal treatment at 200°C for 4 h in vacuo after N-methyl-2-pyrrolidone was evaporated from the IEP precursor solutions to which the silanol tetrahydrofuran solution and Bis(trimethoxysilylpropyl)amine (BisA) were added. The use of BisA possessing a reaction site with a carboxylic acid group on the IEP precursors improved the degree of compatibility between the IEPs and silica. Transparent composites were obtained when the concentration of SiO 2 was below 22 wt %. FT-IR analyses confirmed that the composite was a segmented hybrid material composed of the PTMO segment, the imide segment, and SiO 2 . The silica matrix obtained via silanol sol from water glass and the silica matrix obtained by the conventional sol-gel process with an alkoxysilane were essentially the same, and there was no significant loss of silicon due to incomplete hydrolysis of the alkoxides when preparing composites via the water glass route, in contrast to the situation that can occur in the case of the sol-gel route. Dynamic mechanical and thermal analyses suggested that microphase separation between the imide segment and the PTMO segment occurred in the composites and that there was a substantial amount of phase mixing at the same time. The formation of the silica composite had a great influence on the mobility of the segmnets in the phase-mixing domain. TGA analyses indicated that the formation of the 10 wt % silica hybrid gave a composite with a 50°C higher degradation temperature.

Modification of biodegradable polylactide by silica and wood flour through a sol–gel process

“…The reason for this is the large difference in the surface energy between WF and the PLA matrix. 20 For the PLA-g-AA/SiO 2 (7.7 wt %)/WF(30 wt %) blend, as shown in Figure 6(B), there is a better dispersion and homogeneity of the WF in the PLA-g-AA/SiO 2 matrix. It can also be seen from Figure 6(B) that better wetting is obtained since layers of the matrix material have been pulled out together with the WF, covering the entire WF.…”

“…It is now possible to prepare polymer/ceramic hybrids via molecular-level manipulation using a sol-gel process to create novel materials. [12][13][14][15][16][17][18][19][20] The promise of these new hybrid materials is a controllable combination of benefits of polymers (e.g. flexibility, toughness, and easy processing) and ceramics (e.g.…”

Functionalized SWNT/polymer nanocomposites for dramatic property improvement

“…Polymer nanocomposites have received intense attention and research in the past five years, driven by the unique properties of the nanoparticles and potential to create new material systems with superior properties 1–5. A variety of nanoparticle morphologies have been considered, including spheroidal particles such as silica,6, 7 platelets such as clay8, 9 and graphite,10–12 and nanotubes including multiwall (MWNT) and single‐wall (SWNT) forms 13–17. Among these, SWNTs have been intensively investigated because of their unique one‐dimensional structure with adjustable electric conductivity and robust mechanical properties.…”

Synthesis and application of a silica nanocomposite filler using water glass and a resole‐type phenol resin

“…Reports on the utility of these developments are restricted to thick films or coating materials, therefore there are a few reports that cover these results 18. Although silica‐hydrosol methods have been tried, which involves an inorganic–organic hybridization using water glass, there are only a few successful examples in which it has been possible to achieve the desired utility and to maintain functionality at the same time 19, 20. Our new approach to plastics that offers both utility and functionality is based on the use of a conventional nanocomposite filler.…”

“…18 Although silicahydrosol methods have been tried, which involves an inorganic-organic hybridization using water glass, there are only a few successful examples in which it has been possible to achieve the desired utility and to maintain functionality at the same time. 19,20 Our new approach to plastics that offers both utility and functionality is based on the use of a conventional nanocomposite filler. It is possible to prepare nanocomposite fillers from plastics (resoletype phenol resin) and a silica sol, which prepared from water glass.…”