Plate-like structures

The layers in the plate-like structure of talc are Joined by very weak van der Waals forces, and therefore delamination at low shear stress is produced. The plate-like structure provides high resistivity, and low gas permeability to talc-filled polymers. Furthermore, talc has several other structure-related unique properties low abrasiveness, lubricating effect, and hydrophobic character. Hydrophobicity can be increased by surface coating with zinc stearate. 

Colour variable pigments in our Variocrom range are made of pi-large aluminium flakes which are covered by several layers of Si02 and Fe203, each a few hundred nanometers thick. This multi-layer plate-like structure produces an angle dependent, iridescent colour play. The Si02-layer with a... 

According to Ro et al.17 gels made from low water content sols contain residual organic groups, caused by incomplete hydrolysis, which contributes to the formation of micropores during the thermal treatment. Acid-catalyzed gels show slit-shaped micropores and have a fibrous or plate-like structure. Base-catalyzed gels have cylindrical pores and spherical particles. 

Its plate-like structure provides talc-filled materials with important properties, such as, high resistivity and low gas permeability. This comes about because the diffusion path is so complicated. Several other unique properties of talc are structure-related, including its lubricating effect, caused by its easy delamination its low abrasiveness, because talc is the softest mineral in the Mohs hardness scale and the hydrophobic properties of its surface. Hydrophobicity can be increased even more by surface coating with zinc stearate. Figure 2.63 shows the plate-like structure of talc. 

Figure 8.13 shows relationships for 3 materials. " Both calcium carbonate and talc generate an increased modulus whereas the addition of an elastic material such as EPR slightly reduces the value of Young s modulus. The theory predicts this because filler is composed of rigid particles, for example, calcium carbonate or talc. Better adhesion and plate like structure of talc are instrumental in rapid increase of Young s modulus. 

Mica is an example of a material that forms very thin flakes. The characteristic dimensions are similar to the dendritic particles— thickness and width across the flake. Figure 9.3.e shows plate like structures of abhurite. 

Warpage, usually of plate-like structural components, of course correlates closely with shrinkage. Whenever shrinkage is asymmetrical, i.e. anisotropic, warpage occurs in moldings with frozen internal stresses. 

H.S. Jeong, Y.K. Ko, Y.H. Kim, D.K. Yoon, H.-T. Jung, Self assembled plate-like structures of single-walled carbon nanotubes by non-covalent hybridization with smectic hquid crystals. Carbon 48, 774-780 (2010)... 

Kaolin or clay, its more common name, is a naturally occurring mineral with the chemical formula Al Si, 0, (OH)5. It has a plate-like structure, and is refined and treated for specific uses, the largest of which is the paper industry. Metakaolin, produced by the dehydroxylation of kaolin, is often used to improve the electrical properties of PVC wire and cable compounds. At loadings of about 30 weight percent of the resin in a wire and cable PVC formulation, a doubling of the volume resistivity can be achieved. 

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