Synthesis of a liquid zirconium hybrid resin and the ability of the resin to accelerate the curing of a transparent silicone-modified cycloaliphatic epoxy nanocomposite

Abstract

A liquid zirconium hybrid resin (Zr–QR) was synthesized through sol-gel reactions of zirconium butoxide with silanol-terminated polydimethylsiloxane (DMS-S12) and γ-glycidoxypropyltrimethoxysilane (Z-6040). The sol-gel reactions were monitored using Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance spectroscopy. The Zr–QR morphology was investigated using field emission transmission electron microscopy. The Zr–QR had a well-ordered morphology and the dimensions were less than 5 nm. These properties were achieved because DMS-S12 was used to separate the zirconium clusters and Z-6040 was used to stabilize the Zr–QR. The acceleration of the curing reaction between silicone-modified cycloaliphatic epoxy (SEP) and methylhexahydrophthalic anhydride (MHHPA) caused by the Zr–QR was investigated. Differential scanning calorimetry and FTIR spectroscopy investigations showed that the Zr–QR first reacted with MHHPA, producing chelating ligands and carboxylic acid. Unlike in the conventional method (adding acetic acid to cause non-reactive chelating ligands to form), the carboxylic acid produced effectively accelerated the curing reaction between the SEP and MHHPA. The chelating ligand produced from the Zr–QR and MHHPA suppressed the gelation of the Zr–QR itself during the nanocomposite (SEP–Zr–QR) curing process. The cured SEP–Zr–QR nanocomposite exhibited excellent optical transmittance at visible wavelengths.© 2015 Society of Chemical Industry