Titania pigments

Scanning electron photomicrographs of typical rutile titania pigments treated with various organic and inorganic coatings are provided in Figures 10.4 and 10.5. 

Organic coatings are generally utilized to improve dispersability and flow characteristics of titania pigments. A fascinating array of substances are either used commercially or have been claimed as useful in the patent literature [6], Organics held in place simply by electrostatic forces [7] as well as those cemented to the surface by use of covalent bonds are known [8], The latter are inert to diffusion through the polymer matrix. Said diffusion can lead to end-use problems that include such phenomena as loss of low-temperature heat seal and poor printability. 

The methods whereby titania pigments are incorporated into plastic matrices are diverse. Multiple options exist for the plastics processor, including solid concentrates, direct end-use pigmentation, simple dry blends, or the use of liquid colorants. A simplified breakdown of how major resin categories are pigmented is shown in Table 10.1. 

A significant cation effect (with potentials in KCl higher than those in NaCI) in the acidic range is reported in [521], Unusual effects of the nature of 1-1 electrolytes on the electrokinetic behavior of a titania pigment (surface-modified with silica, alumina, and organic groups) are reported in [516]. 

Farrokhpay, S. et al.. Influence of polymer functional group architecture on titania pigment dispersion. Colloids Surf. A, 253, 183, 2005. 

Labib, M.E. and Williams, R., An experimental comparison between the aqueous pH scale and the electron donocity scale. Colloid Polym. Sci., 264, 533, 1986. Morris, G.E. et al.. Surface chemistry and rheological behaviour of titania pigment suspensions. Colloids Sutf. A, 155, 27, 1999. 

Djerdjev, A.M., Beattie, J.K., and O Brien, R.W., Coating of silica on titania pigment particles examined by electroacoustics and dielectric response, Chem. Mater., 17, 3844, 2005. 

Oguchi, T., Tamatani, M., and Koishi, M., Contact electrification and zeta potential in titania pigments, Nippon Kagaku Kaishi, 6, 902, 1984. 

High-power compound optical microscope 0.25 SOO Titania pigment, cigarette smoke... 

Solomon, D. H., and D. G. Hawthorne. Chemistry of pigments and fillers. Chapter 2, p. 51, in Titania Pigments. New York John Wiley ... 

TABLE 3.3 Chemiluminescence Under Nitrogen at 170°C of Metallocene Polyethylene Films Containing the Nano and Micron Grade Titania Pigments at 0.5% w/w Concentrations with 0.05% w/w Irganox 1010 Antioxidant Together with Control Unpigmented Samples... 

The work of Her and his co-workers led to the creation of new materials and industries. His studies of the surface chemistry of silica led to the invention of unique organophilic and hydrophobic silica products termed estersils . Virtually a new industry was created when he rendered titania pigment particles in organic films and finishes photochemically inert by coating them with silica. 

Silica coatings are applied to particulate materials to modify surface characteristics that interfere with the exploitation of desired bulk properties, as with titania pigments that may photocatalyze the degradation of their vehicle, surfaces of selective zeolite catalysts that may promote undesired reactions, and fillers for plastics that may not disperse in their matrix. 

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