Study on Dielectric and charge transport behavior in alkali-treated randomly oriented Sunn Hemp Fiber Reinforced epoxy composite in connection with the microstructure of fiber

Abstract

The present research introduces alkalization (KOH) of Sunn Hemp (Crotalaria juncea) fiber with various alkali concentrations (5, 10, 15, and 20 wt %) and the soaking periods (2 hr, 4 hr, 6 hr, 8 hr, and 10 hr). All the composites are fabricated using the hand layout method to study dielectric properties. Dielectric constant $$({\rm{\varepsilon {^{\prime}}}}$$) and loss (tan δ) are found to be less in 10% treated composite soaked for 6 hr (10 K6) and may attribute to the decline of water affinity polar groups that result in reducing the effect of space charge polarization. The ac conductivity investigation of composites results in an increasing trend accompanied by the concentrations and soaking time, revealing the evolution of charge carriers in the amorphous phase due to excess alkali supply to the fiber. The highest $${\rm{\varepsilon {^{\prime}}}}$$ and tan δ is obtained in 20 K10 composite assignable to the augmentation of polar groups by forming more amorphous components.

Keywords

• structure
• morphology
• thermoset
• composite
• dielectric properties
• crosslinking