Acrylic‐Based Polyurethane/Silica Hybrids Prepared by Acid‐Catalyzed Sol–Gel Process: Structure and Mechanical Properties

Abstract

Summary: Silica sols were first prepared based on different ratios of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) by an acid‐catalyzed sol–gel process, and then incorporated into acrylic‐based polyurethanes. The structures and morphologies of silicone‐oxo clusters were studied by 29Si NMR, SAXS, and scanning electron microscopy (SEM), whereas the mechanical properties of polyurethane/silica hybrids were characterized by DMA and tensile tests. The silicone‐oxo clusters in both silica sol and polyurethane hybrids became denser and larger at a higher molar ratio of TEOS/MTES and higher silica content, and the silica‐oxo clusters of polyurethane/silica hybrids even became more compact and larger than those of silica sols, increasing the elastic modulus and tensile strength of polyurethane/silica hybrids.Typical structure of silica sol prepared from the hydrolysis and condensation of TEOS and MTES with acid as the catalyst.magnified imageTypical structure of silica sol prepared from the hydrolysis and condensation of TEOS and MTES with acid as the catalyst.

Preparation and Properties of Aqueous Castor Oil‐based Polyurethane–Silica Nanocomposite Dispersions through a Sol–Gel Process

“…[14] PU-Si2 has a chemical shift similar to the silica prepared from MTES, indicating the successful formation of silica nanoparticles from the APTES. Specifically, three peaks are observed as shown in Figure 1.…”

“…Figure 1 shows the solid state 29 Si NMR spectra of PU–Si2. Unmodified silica usually has a chemical shift around –100 ppm and the silica prepared from methyltriethoxysilane (MTES) has a chemical shift around –60 ppm 14. PU–Si2 has a chemical shift similar to the silica prepared from MTES, indicating the successful formation of silica nanoparticles from the APTES.…”

Preparation and Properties of Biobased, Cationic, Waterborne Polyurethanes Dispersions from Castor Oil and Poly (Caprolactone) Diol

“…[14,15]. To improve these properties, great effort has been made to accelerate the development of WPUs [16][17][18][19].…”