Alumina Surface Treated Pigmentary Titanium Dioxide with Suppressed Photoactivity

Abstract

The aim of the optimization of the technological process was to coat the surface of the pigment in a controlled manner and to supress photoactivity in the titanium dioxide (TiO2) pigment. As part of this research, a systematic approach to TiO2 pigment surface treatment with alumina was conducted. Surface treatment with alumina plays a significant role in the improvement of TiO2 properties (e.g. weather resistance and photostability). This research encompasses a raw material analysis and process conditions study. Sodium aluminate and aluminium sulphate were used as a source of alumina hydroxide. The effectiveness of surface treatment was determined using scanning-transmission (STEM) and transmission (TEM) electron microscopy. The photoactivity of pigmentary TiO2 was determined before and after surface treatment. A controlled surface treatment process resulted in pigmentary TiO2 particles with uniform amorphous layers, which supressed the photoactivity of the pigment.

TiO2 Applications as a Function of Controlled Surface Treatment

“…In such a case, heterogeneous precipitation is Figure 8. At pH higher than the IEP, the number of ─OH groups on the particle surface that could provide protons is large and the condensation with the OH─Al species easily occurs [13]. preferred.…”

“…However, some of the components can be co-precipitated to alter the pigment characteristics [1]. There are many works regarding this subject in literature [4][5][6][7][8][9][10][11][12][13][14].…”

Surface Coating of Titanium Dioxide Nanoparticles with a Polymerizable Chelating Agent and Its Physicochemical Property

“…18,19 ROS cause the deterioration of proteins, lipids, and even DNA and disturb cell signaling. 20,21 In previous studies, encapsulating TiO screening effect of TiO 2 NPs and could reduce the generation of ROS, 1,22 conformal surface coating of inert TiO 2 NPs without binding molecules is still challenging. Moreover, it was reported that a high ROS generation level was detected from silica-alumina-coated TiO 2 NPs.…”

“…The annual production of inorganic sunscreen agents, such as titanium dioxide and zinc oxide, according to the exposure increment of ultraviolet wavelength to the earth’s surface, has been increasing for decades. 1 , 2 Among those, titanium dioxide nanoparticles (TiO 2 NPs) have been most widely utilized as an ultraviolet wavelength (UV) screening material to prevent photodegradation of various commercial products, including polymers, textile, paint, personal care products, and cosmetics. 1 − 8 However, the strong aggregation and sedimentation properties make TiO 2 NPs hard to disperse and stabilize in dispersing media with high content.…”

“… 1 , 2 Among those, titanium dioxide nanoparticles (TiO 2 NPs) have been most widely utilized as an ultraviolet wavelength (UV) screening material to prevent photodegradation of various commercial products, including polymers, textile, paint, personal care products, and cosmetics. 1 − 8 However, the strong aggregation and sedimentation properties make TiO 2 NPs hard to disperse and stabilize in dispersing media with high content. 9 − 11 Furthermore, the high level of the chemical potential can make TiO 2 NPs produce reactive oxygen species (ROS) under UV irradiation.…”