Poly(siloxane‐urethane) crosslinked structures obtained by sol‐gel technique

Abstract

Poly(siloxane‐urethane) crosslinked structures were prepared from isophorone diisocyanate, α,ω‐bis(hydroxybutyl)oligodimethylsiloxane and a new hybrid diol containing hydrolysable SiOC2H5 groups besides OH groups. The latest was synthesized by the acid‐catalyzed reaction between 1,3‐bis(3‐glycidoxypropyl)tetramethyldisiloxane and 3‐aminopropyltriethoxysilane. The formations of the urethane groups along the polymer backbone as well as the formation of the silica domains were first confirmed by the presence of the specific bands in Fourier transform infrared spectra. The resulted materials were characterized using differential scanning calorimetry, thermogravimetric analysis and scanning electron microscopy. The results of the dynamic mechanical analysis (DMA) performed at various frequencies revealed shape memory capabilities for some of the obtained structures. The silica formed because of the hydrolysis‐condensation reactions proved to have reinforcing effect upon siloxane‐urethane structure also evidenced by DMA and increasing water vapor sorption capacity as was measured by dynamic vapor sorption. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Analysis of dynamic mechanical, thermal and surface properties of poly(urethane-ester-siloxane) networks based on hyperbranched polyester

“…5b). When compared with literature data, it can be observed that rubbery plateau modulus of the investigated PU networks are higher than values determined for other type of crosslinked poly(siloxaneurethane)s [30], as well as for PUs synthesized with different macrodiol and crosslinked with Boltorn® HBP [9].…”

Poly(urethane-siloxane)s based on hyperbranched polyester as crosslinking agent: Synthesis and characterization

“…The EDX analysis, performed to identify the type of the atoms present in the polyurethane samples at a depth of 100-1000 nm from the surface, 22 confirmed the presence of all expected elements (C, O, Si and N). The results obtained from EDX analysis are displayed in Fig.…”

Studies of the Thermal and Mechanical Properties of Poly(urethane–siloxane)s Cross-Linked by Hyperbranched Polyesters

“…This observation indicates that cohesion and stability of the PU network are not destroyed under the investigated experimental conditions. 31 In addition, Figure 4 shows that during the glass transition of the soft segment, the G′ of the synthesized PUs slightly decreases, while in the glass transition region of the hard segments G′ rapidly decreases as a consequence of the increased mobility of the chains. On the other hand, the presence of the chemical cross-links restricts the flow of the polymer in the rubbery plateau (around 130°C…”