Influence of the physical and chemical surface structure on thewater adsorption characteristics of insulation materials

摘要

Recent work is indicating, that the insulation characteristics ofinsulation material surfaces are influenced by the relative humidity ina greatly differing extent. This work has demonstrated, that thisinfluence mainly depends on the physical and chemical surface structuresof insulation materials. Additives such as hardeners and fillers, whichare added in different amounts to the respective base material, have animportant influence on the surface roughness and the chemical compoundof insulation materials. This leads to a different behaviour ofinsulation material surfaces with respect to the adsorption of watermolecules. Therefore in this paper we try to clarify the influence ofphysical and chemical properties of insulation material surfaces ontheir water adsorption characteristics. In order to describe thephysical structure of insulation material surfaces we performed the REMspectroscopy and we determined the specific surface area. Additionally,the energy disperse X-ray (EDX) analysis has been applied in order toinvestigate the chemical compound of the test specimen. Allinvestigations have been carried out on the test specimen consisting oftwo different glass fibre reinforced resins (epoxy and polyester resin).Furthermore, a laminate consisting of presspan and polyester foil hasbeen investigated. The achieved test results show, that the laminateconsisting of presspan and polyester foil shows the best insulationcharacteristics of the investigated insulation materials under highhumidity, although it has the largest specific surface area andtherefore-as we will show-is the most hydrophilic material