Studying the Ultrasonic Properties, DC Conductivity and Coefficient of Thermal Conductivity of PVA-Egg Shells
Composites
Hani Mahmood Hussien*
Department of General Science, College of Basic Education, University of Babylon, PO box 4, Iraq
* E-mail : hanim752003@yahoo.com
Abstract
The polymer composite used in the present study were made of polyvinyl alcohol (PVA) as a matrix and Iraqi
egg shells as filler. Polymer composites were fabricated by mixing PVA with (5, 10, 15, 20, 25, 30, 40 and 50)
wt.% of egg shells powder by using a magnetic stirrer at temperature 900C for 4hr to obtain homogeneous
solution then samples were prepared by casting techniques. The ultrasonic measurements (transmittance,
absorption coefficient and relaxation amplitude, acoustic impedance, compressibility and compressibility) of
composites were carried out by using ultrasound technique. Measurement of DC conductivity and coefficient of
thermal conductivity were done as a function to wt. % of egg shells. It was found that the samples contain
additives of eggshells 5%, 10%, 20% and 30%, the attenuation decreased by increasing frequency up to 40 KHz
and then increased after this frequency; while the sample contains 15% of the eggshells, the attenuation not alter
significantly with increasing frequency. Sample with 50 % egg shell has two peaks at 20 and 30 kHz. As can be
seen that the samples which contain a proportion of eggshells 5, 10, 20, 25, 30 and 40%, the transmittance
coefficient increases with increasing frequency up to 40 kHz and then decreases and relaxation amplitude
decreases with increasing frequency from 5 to 50 KHz. Generally observed acoustic impedance decreases with
increasing eggshells except percentage 20%, where the highest value for the impedance. Compressibility
generally increases with increasing of eggshells up to 40 % and then decreases. The electrical conductivity
increase as concentrations of egg shells increase up to 30 % then conductivity decreases at 40 % then increases
slightly at 50 %. It was found that coefficient of thermal conductivity increases with increasing of egg shells up
to 40 % then decreases.