Electrical and Dielectric Properties of Discs Fabricated Using Periwinkle Shell Nanopowder and Dry Cassava Starch

Periwinkle shells and cassava effluent are wastes generated in very large quantities and majorly under-utilized. Due to existence of inefficient waste management systems in developing countries, their disposal is by indiscriminate dumping, a practice that adversely affects the environment and human health. Hence, there is an urgent need to examine their potentials for possible engineering applications in order to further proffer a safe way of managing them. In this work, Periwinkle shell nanopowder and cassava starch were prepared from the wastes and then used to fabricate disc-shaped samples. The samples were developed with various lengths/thicknesses and in triplicates, after which their electrical and dielectric properties were evaluated. For lengths/thicknesses of 2.6 mm to 6.5 mm, the mean electrical resistance and electrical resistivity obtained were (9.89 to 23.00) × 10⁶ Ω and (8.231 × 10⁵) Ωm respectively. Over the temperature range of 20°C to 50°C, the respective results for thermal sensitivity, activation energy, and temperature coefficient of resistance assessment were (6982 ± 158) K, 0.60 eV, and −8.12 %/K. More so, it was observed that quality factor increased with sample’s thickness and frequency of applied signal. With increase in frequency from 0.10 kHz to 100.00 kHz, the dielectric constant of the studied sample decayed exponentially from (20.54 ± 0.04) to (1.67 ± 0.01). Aside meeting the market requirements for NTC thermistors, it was found that the sample could serve as a suitable alternative to conventional dielectrics like mica, paper, plastic film, tantalum oxide, and aluminium oxide for production of capacitors.