Isocyanate-modified Nano-SiO₂ and Corresponding Process Optimization

Abstract

Abstract. Nano-SiO 2 is hydrophilic, and the surface of nano-SiO 2 should be modified to improve its dispersion in a polymer matrix. Here, triallyl isocyanurate was selected to modify the surface of the nano-SiO 2 powders. Because the reaction between isocyanate groups (-NCO) and hydroxyl groups (-OH) on surface of the nano-SiO 2 does not need any pre-treatment, one single and simple step can facilitate the graft. By optimizing the specific modification process via orthogonal experiments, optimal processing conditions that yield good graft modification effects are obtained. This enhances the lipophilicity of the nano-SiO 2 . The Fourier-transform infrared spectrometer (FTIR) results indicate that the isocyanate groups (-NCO) in triallyl isocyanurate and the hydroxyl groups (-OH) on surface of the nano-SiO 2 undergo a chemical reaction. Further, the precipitation data show that modified nano-SiO 2 is well dispersed in the organic phase, and its hydrophobic property is strong. This fulfills the goal of modifying nano-SiO 2 powders.

Highly transparent castor oil‐derived polyurethane/silica nanocomposite coating synthesized by in situ polymerization

“…The absorption peak was observed at 1690 cm −1 in TI–NS, which indicates fewer hydroxyl groups whereas the peak corresponding to 1456 cm −1 revealed the presence of CN absorption. Ye et al have reported similar findings 18 …”

“…Ye et al have reported similar findings. 18 As observed from Figure 1C, the FTIR spectra of the CP showed NH stretching at 3366 cm À1 , while in the case of PU…”

“…The resultant solution was then centrifuged and washed for purification. The solution mixture was then dried in a vacuum oven for 8 h at 70°C to get the modified NS particles 18 …”

“…The solution mixture was then dried in a vacuum oven for 8 h at 70 C to get the modified NS particles. 18…”

“…In comparison to other isocyanates like toluene diisocyanate, TI does not need any pretreatment process with a better grafting modification. 18 Based on the above study, the current article focuses on the synthesis of a highly transparent polyurethane/nano-silica hybrid coating applicable as a clear coat in the automotive paint industry. Isophorone diisocyanate (IPDI) has been used as a curing agent and dibutyltin dilaurate (DBTDL) as a catalyst, with xylene as the solvent medium.…”