Isolation of Sunn Hemp fiber by microwave irradiation and its effect on reinforced epoxy composite for electrical application

Abstract

The present study investigates the microwave treatment of Sunn Hemp bast fiber and its epoxy polymer composites. The fibers are exposed under microwave at various power (160 W, 320 W, and 480 W) with varied showing times (2, 4, 6, 8, and 10 min). The substantial change in fiber structure due to treatment are characterized structurally. A reasonable incremental trend in the degree of cellulose crystallinity and crystallite size is observed where microwave power raised from 160 W to 320 W along with the exposure time. The highest CI (80.5%) and CS (41.2 Å) are observed in fiber treated at 320 W for 2 min (320 W 2 M). The uneven morphology is observed in all treated fiber from Field Emission Scanning Electron Microscopy (FESEM), which ascribes the enhancement in the fiber structure. Fourier Transmission Infrared (FTIR) Spectra reveals the unaltered structure of microwave-treated fibers. The dielectric investigation was performed on the Sunn Hemp fiber-reinforced composite, where dielectric constant (ε’) and dielectric loss (Tan δ) show a significant decrement in the treated composite specimen. The decrement is due to the absorbance of the polar hydroxyl group upon the irradiation that lowers the polarity in fiber, hence reduces ε' and Tan δ. The conductivity data of composite shows a falling trend as microwave power increases with the exposure time due to reducing the polar hydroxyl groups from the fiber structure. The impedance graph explains the non-Debye type of electrxal relaxation in the composites system.