Photopolymerization synthesis of polyacrylic acid dispersant with methoxysilicon end groups and its application in a nano‐SiO₂ aqueous system

Abstract

In order to improve the dispersity and stability of the 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 (KH590). After adding KH590‐PAA into the nano‐SiO2 aqueous dispersion system (20 wt% solid content), the viscosity and the curing time of the system were measured with a rotational viscometer and the inverted bottle method. Moreover, the dispersion mechanism of KH590‐PAA for the nano‐SiO2 aqueous system was researched by measuring the adsorption capacity, the particle size and the zeta potential of the nanoparticles with a conductivity meter, dynamic light scattering, SEM and TEM, respectively. The results showed that the 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 the SiO2 nanoparticles could be further 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. © 2018 Society of Chemical Industry

Double cross-linked transparent superhydrophilic coating capable of anti-fogging even after abrasion and boiling

“…4,5 In water dispersion systems, due to their characteristics of long molecular chains, adjustable structure, and easy introduction of polar groups (such as –COOH, –SO 3 H and –NH 2 ), organic polymer, and inorganic oxide particles can provide steric hindrance and electrostatic repulsion for particles through physical adsorption, thus improving the dispersion and stability of the system. 6,7 In this context, cross-linking of inorganic NPs with organic polymers has been the focus of attention since 2000. 8–10…”

“…4,5 In water dispersion systems, due to their characteristics of long molecular chains, adjustable structure, and easy introduction of polar groups (such as -COOH, -SO 3 H and -NH 2 ), organic polymer, and inorganic oxide particles can provide steric hindrance and electrostatic repulsion for particles through physical adsorption, thus improving the dispersion and stability of the system. 6,7 In this context, cross-linking of inorganic NPs with organic polymers has been the focus of attention since 2000. [8][9][10] Due to their large surface area and abundant surface hydroxyl groups, SiO 2 NPs have been used to prepare super/high hydrophilic coatings with surface roughness, which are promising and competitive in a variety of applications, such as solar panels, surface self-cleaning, and anti-fogging glass.…”

Acrylic acid/allyloxy polyethylene glycol copolymer with methoxysilicon end groups as a highly effective dispersant for nano‐SiO2aqueous system

“…When the solid content of the system was 20 wt % and the addition content of the dispersants was 0.1 wt %, KH590‐AA x ‐APEG y ‐5 and KH590‐PAA‐2 with the similar molecular weight in our previous study were selected to research the influence of introducing APEG segment on the dispersion stability of nano‐SiO 2 aqueous system . The results were shown in Table and Figure .…”

“…Allyloxy polyethylene glycol (APEG, M n = 3400 g mol −1 ) was purchased from Jiangsu Hai'an Petrochemical Co., Ltd. (China). KH590‐PAA was synthesized according to the previous work …”

“…After KH590‐PAA was added into the nano‐SiO 2 aqueous system with the solid content of 20 wt %, it could be chemically grafted onto the surface of nano‐SiO 2 , which was beneficial to exerting the electrostatic repulsion and steric hindrance effects of PAA fragments. Therefore, the obtained aqueous system showed good dispersion stability …”