UV- blocking and dielectric properties of polyethersulfone/ nanolignin composites

Agricultural wastes contain many recyclable constituents of versatile properties that enable their utilization in many technological applications. Among these renewable materials, lignin appears as an abundant and affordable biodegradable polymer. In this work, nanolignin (NL) is blended in different ratios with polyethersulphone (PES) namely 0.25, 0.5, 1, and 3%. Casted films prepared from PES/NL composites were thoroughly characterized by FTIR and UV spectroscopy. The films demonstrated high UV absorbance that increases by rising amount of NL in the composite film. Moreover samples PES-NL1.00 and PES-NL3.00 showed ≈ 0.20 % transmittance at 380 nm. Thermal gravimetric analysis revealed enhanced thermal stability of nanocomposite films compared to pure PES. The electric conductivity and dielectric properties are evaluated using the Broadband Dielectric Spectroscopy (BDS) technique. The measurements showed that the prepared films have low permittivity accompanied by a very low dielectric loss. Addition of NL at concentration varied between 0 and 3 wt% to the PES decreases ε′ unsystematically from 4.4 to 3.5 and tan δ from 0.008 and 0.005. On the other hand, the increase of temperature by 100 o C, increases the permittivity by about 1% indicating the thermal stability against dielectric properties. These UV-blocking and dielectric features make this nanocomposite very promising as high-performance interlayer dielectrics for fabricating semiconductor devices.