Search

Biopolymers obtained from renewable resources became the center of public interest by virtue of their environmental and commercial advantages. Natural polymers such as starch, almond gum, chitosan and arabic gum were investigated to get fully or partially biodegradable dielectric material. Thus, in this article we study the material properties of cashew gum. This biopolymer is an exudate collected from occidental anacardium tree. For this investigation, scanning electron microscopy of powder and thin film cashew gum showed homogenous and slightly rough surface morphology with visible wrinkles. The thermal analyses such as thermogravimetric (TGA) and differential scanning calorimeter were realized. thermogravimetric thermogram shows two distinct stages of decomposition. The first around 150°C is attributed to moisture evaporation with loss in weight of 9.7%. The second transition, between 255°C and 330°C, is related to the decomposition of cashew gum with loss in weight of 50%. UV-visible spectra of the cashew gum thin film show a low absorbance and high transmittance. For this material, we obtained a direct optical band gap around 4.56 eV. In addition, the dielectric and electrical characterizations lead to conclude that cashew gum may be interesting for transistor applications as a gate dielectric. [ABSTRACT FROM AUTHOR]

In this paper, we study the dielectric and material properties of almond gum, a natural biopolymer material collected from almond trees. The dielectric properties are investigated by mean of impedance spectroscopy in the ranges of frequency 40 Hz-10MHz and temperature 300 K–400 K. The resulting responses provided valuable information about the material and revealed that the dielectric parameters are both temperature and frequency dependent. The calculated dielectric constant is around 8 at temperature T = 300 K and frequency f = 1 kHz. UV–visible spectrum of the almond gum thin films recorded from 300 nm to 2500 nm, showed a high transmittance with an optical band gap around 3.4eV. X-ray fluorescence showed that almond gum contained oxides such as CaO, SiO 2 , K 2 O, etc, with a significant concentration of CuO (63.72%) and several other chemical elements in trace such as strontium, rubidium, chlorine, cadmium, sulfur, etc. Thermal properties studies such as thermogravimetric analysis and differential scanning calorimetry conducted on almond gum powder revealed two stages of decomposition with a glass transition at 58.5 °C. In order to study the surface properties of almond gum thin films, we have carried out contact angle measurements and scanning electron microscopy analysis. The results showed hydrophobic surfaces. Our findings in this study lead to conclude that almond gum may be an interesting candidate for electronic applications especially for gate dielectric and encapsulating layer. • Almond gum, a natural biopolymer material, thin films were deposited by spray pyrolysis technique. • The dielectric constant is around 8 at temperature T = 300 K and frequency f = 1 kHz. • High transmittance between 300 nm and 2500 nm with an optical band gap around 3.4eV. • X-ray fluorescence showed that almond gum contained oxides (CaO, SiO 2 , K 2 O, CuO.) • Thermal properties revealed two stages of decomposition with a glass transition at 58.5 °C. [ABSTRACT FROM AUTHOR]