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Hydrolysis kinetics of silane coupling agents studied by near-infrared spectroscopy plus partial least squares model
摘要： A method of Fourier transform near-infrared (FT-NIR) spectroscopy combined with partial least squares (PLS) model was successfully applied to investigate the hydrolysis kinetics of four kinds of silane coupling agents (phenyltriethoxysilane, vinyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-chloropropyltriethoxysilane) in an acid-catalyzed EtOH system. The fast scanning speed and high sensitivity of the FT-NIR spectroscopy, and the powerful data processing ability of the PLS, enabled the method to quantitatively and accurately catch the fast changing H2O concentration during the hydrolysis processes without delay, realizing the study of the fast-paced hydrolysis reactions of the silane coupling agents. The results showed that electrophilic substitution occurred in the hydrolysis reactions, which followed second-order reactions and greatly depend on the catalyst concentration and reaction temperature. The hydrolysis rate constants, activation energy, and Arrhenius Frequency factors were gained. In conclusion, the FT-NIR PLS model is a powerful tool for hydrolysis kinetics researching of the silane coupling agents.
关键词： partial least squares,Hydrolysis kinetic,silane coupling agent,near infrared
更新于2025-09-23 15:22:29
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Photopolymerization synthesis of polyacrylic acid dispersant with methoxysilicon end groups and its application in nano-SiO <sub/>2</sub> aqueous system
摘要： In order to improve the dispersity and stability of nano-SiO2 aqueous system with high solid content, a kind of polyacrylic acid dispersant with methoxysilicon end groups (KH590-PAA) was synthesized by photopolymerization of acrylic acid (AA) initiated with (3-mercaptopropyl)trimethoxysilane (KH-590). After adding KH590-PAA into nano-SiO2 aqueous dispersion system (20 wt% solid content), the viscosity and the curing time of the system were measured by rotational viscometer and the inverted bottle method. Moreover, the dispersion mechanism of KH590-PAA for nano-SiO2 aqueous system was researched by measuring the adsorption capacity, the particle size and the zeta potential of nanoparticles with conductivity meter, dynamic light scattering (DLS), scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. The results showed that methoxysilicon groups in KH590-PAA could react with hydroxyl groups on the surface of nano-SiO2 in the process of stirring, which enhanced the adsorption capacity of the dispersant and then increased the surface charge of the particles. Therefore, electrostatic repulsion and steric hindrance effects between SiO2 nanoparticles could further be enhanced by adding the KH590-PAA dispersant, and then the nano-SiO2 aqueous system exhibited better dispersity and stability. Besides, the dispersion properties of SiO2 nanoparticles in water were closely related to the addition amount and the molecular weight of the KH590-PAA dispersant.
关键词： Dispersion,Photopolymerization,Silane coupling agent,SiO2 nanoparticle,Polyacrylic acid
更新于2025-09-10 09:29:36