Feasibility Study of Microwave Welding of Polypropylene Using Silicon Carbide Nanowhiskers as Microwave Susceptor

Abstract

Currently, welding is the most efficient way for joining of plastic. Due to its rapid heating, efficiency in term of time and energy, and ability to be applied on components of any shape, microwave welding stands out from other welding methods. Additionally, SiCNWs was proposed as the microwave susceptor for the microwave welding of thermoplastic in this work due to its high dielectric loss and biocompatibility. To produce microwave welded joint, SiCNWs was first mixed with acetone to obtain a SiCNWs suspension. After that, SiCNWs was drop casted onto the targeted area of PP, allowed to dry and then microwave irradiated. In this work, the microwave heating time studied ranged from 15 s to 20 s. SEM and single lap shear test were used to characterise the microwave welded joint. From the findings, the tensile strength increased as the microwave heating duration increased from 15 s to 18 s, due to formation of SiCNWs/PP nanocomposite welded joint layer with increasing thickness. Yet, when the microwave heating time was prolonged to 20 s, the tensile strength decreased to 0.85 MPa. Besides, a void was observed at the welded joint and it is believed that the presence of void causes the welded joint to weaken when force is applied. Under properly regulated of microwave heating time, a strengthened nanocomposite welded joint can be produced which demonstrate great promise in plastic welding.