Dielectric properties of glassy disaccharides for electromagnetic interference shielding application

• Published in: Journal of applied physics 2015-11, Vol.118 (18)
• Main Authors: Wlodarczyk, P., Hawelek, L., Paluch, M., Wlodarczyk, A., Wojnarowska, Z., Kolano-Burian, A.
• Format: Article
• Language: English
• Subjects: Applied physics; Binary mixtures; Dielectric loss; Dielectric properties; Disaccharides; Electromagnetic radiation; Electromagnetic shielding; Energy dissipation; Glass transition temperature; Lactulose; Microwave absorbers; Microwave frequencies; Sucrose; Sugar; Trehalose
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4935271

Three amorphous disaccharides (sucrose, trehalose, and lactulose) and their mixtures were studied in order to evaluate their ability to absorb a high frequency (>1 MHz) electromagnetic wave. The materials were characterized by a dielectric loss tangent. It was found out that the highest tan(δ) value is observed in pure amorphous sucrose (tan(δ) = 0.17 at f = 1 MHz at T = 293 K). Moreover, the best Tg/tan(δ) ratio is observed in binary mixtures of sucrose and trehalose. A high glass transition temperature is advantageous as it increases operational temperatures of the material. The high tangent delta in microwave frequencies of sugars is connected with the mobility of sugar groups (possibly –CH2OH). The energy of the electromagnetic wave is converted into rotational movements of side groups and in consequence it is dissipated in the form of heat. It was proven that the polar low molecular glasses such as sugars may form dielectric components of composite microwave absorbers.