Triboelectric property

The electrostatic charge on the polymer depends on both the polymer, the material used as the rubber, and the time of rubbing. Test methods for triboelectric properties have been standardized, and triboelectric series for polymers are available. 

After-treated pyrogenic SAS have been used lately to an increasing extent to regulate the triboelectric properties of toner powders. The extent of the effects that can be attained is shown in Table IX. 

Water vapor sorption Isothermal microcalorimetry Intrinsic dissolution Triboelectric property... 

Conversely, by constructing the filter medium with a blend of fibres of widely contrasting triboelectric properties, it is claimed by a fibre manufacturer that superior collection efficiency can be obtained. It is further claimed that, by virtue of this enhanced efficiency, a more open structure can be used with consequent advantages in respect of the reduced power consumption required to pull the dust-laden air through the collector. However, although this effect has been used to some advantage in clean air room filtration applications, considerably more research is necessary if the triboelectric effects in industrial dust collection are to be fully understood and exploited. 

The adsorption of surface-active materials onto a solid surface from solution is an important process in many situations, including those in which we may want to remove unwanted materials from a system (detergency), change the wetting characteristics of a surface (waterproofing), control the triboelectric properties of a surface (static control), or stabilize a finely divided solid system in a liquid where stability may otherwise be absent (dispersion stabilization). In these and many other related applications of surfactants or amphiphilic materials, the ability of the surface-active molecule to situate itself at the solid-liquid interface and produce the desired effect is controlled by the chemical natures of the components of the system the solid, the surfactant, and the solvent. The following discussions summarize some of the factors related to chemical structures that significantly affect the mechanisms of surfactant adsorption and the orientation with which adsorption occurs. 

Electrical properties of polymers that are subject to low electric field strengths can be described by their electrical conductivity, dielectric constant, dissipation factor, and triboelectric behavior. Materials can be classified as a function of their conductivity (k) in (Q/cm)- as follows conductors, O-IO" dissipatives, and insulators, lO or lower. Plastics are considered nonconductive materials (if the newly developed conducting plastics are not included). The relative dielectric constant of insulating materials (s) is the ratio of the capacities of a parallel plate condenser with and without the material between the plates. A correlation between the dielectric constant and the solubility parameter (6) is given by 6 7.0s. There is also a relation between resistivity R (the inverse of conductivity) and the dielectric constant at 298 K log R = 23 - 2s. 

Plastic-Plastic Separation Both dry and wet processes can be used to separate one plastic from another in a recycling operation. The most common wet separation methods are based on differences in density between particles of different plastics [1, 2, 10, 49], Density is a bulk property of the plastic. Unfortunately, many factors beyond polymer type affect density. Plastic particles can also show differences in surface properties. Plastic-plastic separation methods based on surface property differences include triboelectric separation [75] (a dry process) and froth flotation [75] (a wet process). Density-based and surface-property-based methods for separating a stream of mixed plastics are covered in the following sections. 

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