Thème :
Triboelectric Charging of Polymers
Présentation :
During their use, the insulating materials easily acquire charges by triboelectrifacation. Due to the high electrical resistivity, in low humidity environments, the acquired charges do not easily decay and cause charge build-up in the surface. The study of the generation and the dynamics of the charges on the surfaces insulating materials are very important for the safety of the industrial installations. The tribocharging of polymers depends on the surface properties of the two materials, the nature of the materials coming into contact, the environmental conditions and and physical factors such as surface morphology, contact surface ... etc. The triboelectric charge also depends on the chemical structure of the surfaces. However, the polarity and the amount of charge can be adjusted by modifying the surface properties.
Since the nature of surface chemistry is one of the most important factors determining electrostatic behavior, the control of surface properties should also control the triboelectric properties of the polymer, the introduction of certain functional groups into the surface chemical, will change the electrostatic behavior
Thème :
surface potential decay and Experimental Design methodology
Présentation :
The experimental design methodology is useful for three
objectives: screening, optimization, and robustness testing
. The novelty of this methodology is that it proposes a
factorial experimentation, in which the factors investigated
vary simultaneously. Simple mathematical processing of
experimental design data enables a rather accurate evaluation
of factor effects and interactions. Experimental design can
also be used for determining the relationship between the
factors affecting a process and the output of that process.
Experimental Design methodology proves to be an effective tool
in the analysis of the factors that influence the surface potential
decay
Thème :
Synthetic insulating polymers and surface potential decay
Présentation :
Synthetic insulating polymers are widely applied in electrical
industry due to their excellent electrical, thermal, and mechanical
properties. In many cases, such polymers are used in hostile environments
where they may be subjected to attack by non-ionizing
radiations, water, corrosive materials, etc. Therefore, their properties
are deteriorated and a premature ageing of the electrical
insulation can be observed.
The measurement of the isothermal surface potential decay
after charge deposition provides a convenient method to investigate
the electrical properties of such insulating materials. Its main
interest lies in the avoidance of any contact with the surface under
investigation. This explains the abundance of research work on
surface potential decay measurement in various fields of industry
applications: electro-optics, photocopiers and laser printers,
electrets and insulating polymers for high voltage insulation.
During the last two decades, many theories have been developed
in order to explain the kinetics of surface potential decay on
initially charged insulating polymeric in terms of surface
conduction, charge injection, and polarization.
However, the recent literature on potential decay measurement is
dominated by the hypothesis of the injection into the bulk of the
charge deposited on the surface accompanied by a slow polarization
processes within the bulk under the influence of the
deposited charge. The main experimental result at the origin of
this hypothesis is the ‘‘crossover phenomenon’’, reported initially
by Ieda et al., and then thoroughly documented by other
works.