Influence of humidity on the electrical charging properties of cork agglomerates

• Published in: Journal of non-crystalline solids Vol. 353; no. 47-51; pp. 4501 - 4505
• Main Authors: Lança, M.C., Wirges, W., Neagu, E.R., Gerhard, R., Marat-Mendes, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-12-2007; Elsevier
• Subjects: 77.22.−d; 77.84.−s; 81.05.Rm; Applied sciences; Biomaterials; Electrical and electronic properties; Exact sciences and technology; Paper, paperboard, non wovens; Polymer industry, paints, wood; Properties and testing; Wood. Paper. Non wovens; 77.22.−d; 81.05.Rm; 77.84.−s; Electrical and electronic properties; Biomaterials; Cell structure; Charge carrier trapping; Electric charge; Cork; Tetrafluoroethylene polymer; Humidity; Polymer; Spin-on coating; Biomaterials; Electrical and electronic properties; Agglomerate material; Coatings; 77.22.-d; 77.84.-s; 81.05.Rm
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2007.03.037

Cork is a natural cellular and electrically insulating material which may have the capacity to store electric charges on or in its cell walls. Since natural cork has many voids, it is difficult to obtain uniform samples with the required dimensions. Therefore, a more uniform material, namely commercial cork agglomerate, usually used for floor and wall coverings, is employed in the present study. Since we know from our previous work that the electrical properties of cork are drastically affected by absorbed and adsorbed water, samples were protected by means of different polymer coatings (applied by spin-coating or soaking). Corona charging and isothermal charging and discharging currents were used to study the electrical trapping and detrapping capabilities of the samples. A comparison of the results leads to the conclusion that the most promising method for storing electric charges in this cellular material consists of drying and coating or soaking with a hydrophobic, electrically insulating polymer such as polytetraflouroethylene (Teflon®).