Effect of untreated fiber loading on the thermal, mechanical, dielectric, and microwave absorption properties of polycaprolactone reinforced with oil palm empty fruit bunch biocomposites

Basic research on recyclable, renewable and biodegradable polymer composite materials reinforced with natural fibers is increasingly growing. In this article, we characterize agricultural waste by determining its dielectric properties for microwave absorber application. Recently, polymer composites reinforced with natural fibers are increasingly used in dielectric and aircraft applications. We used a Thermal Hake blending machine to blend oil palm empty fruit bunch with polycaprolactone grain to make a homogeneous powder. The functional groups of the resulting composites were then analyzed through Fourier transform infrared spectrometry. Thermogravimetric and differential thermogravimetric analyses were performed to determine the thermal degradation behaviors of the composites. The tensile strength, tensile modulus and elongation at break of the composites were measured in an Instron universal testing machine. A rectangular waveguide and open‐ended coaxial probe connected to a microwave network analyzer (PNA) Agilent N5230A PNA‐L was used to measure the reflection coefficient S₁₁ and transmission coefficient S₂₁ values and the dielectric properties of the composite materials. Results showed that the thermal stability and dielectric properties of the polymer composites decreased as the fiber content increased. The composites exhibited potential as microwave absorbers at microwave frequencies. POLYM. COMPOS., 39:E1778–E1787, 2018. © 2018 Society of Plastics Engineers