Feasibility study on microwave welding of thermoplastic using multiwalled carbon nanotubes as susceptor

Abstract

Despite manufacturers’ goal of molding single component products from plastics, the structures of some of the products are far too complex to be molded as a single piece. Therefore, assembly of subcomponents into the final products is important for the manufacturing of many plastic-based products. To date, welding is the most efficient joining method for plastics. In this study, multiwalled carbon nanotubes were proposed as the susceptor for the microwave welding of high-density polyethylene considering multiwalled carbon nanotube is a good microwave absorber. multiwalled carbon nanotubes were first dispersed in ethanol in an ultrasonic bath to obtain a homogeneous dispersion. Multiwalled carbon nanotubes dispersion was dropped on the targeted area of the prepared dumbbell-shaped sample and dried in an oven at 45°C for 30 min. The sample was then subjected to 800 W microwave irradiation in the domestic microwave oven. The strength of the weld was tested by using tensile testing. Besides, the cross section of the welded joint was characterized by using scanning electron microscopy. The effect of microwave heating duration and the multiwalled carbon nanotube concentration in the dispersion were studied. It was found that the joint strength increased as the heating duration increase from 2 s to 8 s but decreased when the heating duration was further extended to 10 s. Scanning electron microscopic images showed that voids were formed at the joint interface when 10 s was used and resulted in the lowering of joint strength. In the study of the effect of the multiwalled carbon nanotube concentration in the dispersion, joint strength increased when the multiwalled carbon nanotubes concentration increased from 0.25 wt% to 0.75 wt%. However, the joint strength of sample with 1.00 wt% multiwalled carbon nanotube concentration decreased. The presence of a thick unwelded multiwalled carbon nanotubes layer at the joint interface for sample with 1.00 wt% multiwalled carbon nanotubes concentration as shown in scanning electron microscopic image was believed to cause the lowering of joint strength.

Microwave Welding of Thermoplastic using Silicon Carbide Nanowhiskers as Susceptor: Effect of Heating Duration

“…The microwave absorption performance of carbonaceous materials such as carbon nanotube (CNT) and graphite were widely studied. It is reported that the existence of sp 2 π electrons in carbon structure are responsible for the excellent microwave absorption as well as their heating mechanism [15]. For this reason, carbonaceous materials are suitable to serve as microwave susceptor for microwave welding.…”

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

“…They noted that the welded joint attained higher bonding strength than PP itself and suggested that the formation of composite at the interface was the main reason of high joint strength. Foong et al also studied welding of PP using CNTs alone as susceptor, which is less timeconsuming than using PVA/CNTs composite coating susceptor [16]. However, acidic doping process was needed for conductive polymer before being used as a susceptor, while carbon materials such as CNTs and nano-graphite is carcinogenic to humans.…”

Polypyrrole/ Functionalized Multi-Walled Carbon Nanotube / Nickel Oxide Nanocomposites: Structural, Morphological, Optical and Composition Analysis Studies

“…Additionally, PPy reinforced by functionalized nano-carbon delivers an enhanced morphological features [8]. Continuously, PPy/f-MWCNT is considered as an excellent NCs compounds in which cost-effectiveness, high mechanical strength and chemical stability as well as relatively high electrical conductivity can be obtained; the latter is mainly attributed to the considerable surface area and good adhesion to substrate [9]. Simultaneously, f-MWCNT is a thought provoking reinforcement for polymer composite due to its high aspect ratio, porosity, corrosion resistance, low toxicity and electrical resistance, and large interfacial area [10].…”