Thesis
Additive manufacturing with carbon nanotube enriched acrylonitrile butadiene styrene
Washington State University
Master of Science (MS), Washington State University
2018
Handle:
https://hdl.handle.net/2376/101186
Abstract
Additive manufacturing, also known as 3D printing is an emerging method to produce customized parts with functional materials without big investments. Fused filament fabrication (FFF) uses thermoplastic-based feedstock and has recently been adapted to fabricate composite materials. Acrylonitrile butadiene styrene (ABS) is a very common engineering plastic which is commonly used as FFF feedstock. Carbon nanotubes (CNT) are attractive fillers because of their high aspect ratio, high conductivity and excellent mechanical and physical properties. Therefore, a nanocomposite of these two materials can potentially be electrically conductive with enhanced mechanical properties that is compatible with FFF printing. This work focuses on the investigation of the relationships between the FFF process, CNT concentration and the electrical, tensile, piezoresistive, and fracture properties of the printed ABS/CNT nanocomposites. Nanocomposite filament with CNT concentrations up to 10 wt% were produced for the FFF process using a twin-screw extruder. The feedstock was pellets from a masterbatch containing 15 wt% multi-walled CNT. For the electrical conductivity tests, the effects of the FFF process parameters such as layer orientation, layer thickness, and nozzle size were analyzed. The tensile properties were analyzed together with the piezoresistivity for different CNT concentrations by measuring the resistance while straining the printed tensile specimen. Compression-molded samples were also prepared as the bulk baselines for electrical and tensile tests. With the fracture tests, the influence of CNT on the layer-to-layer bonding strength in the printed parts were quantified. At the proper amount and dispersion of CNT, ABS becomes an electrically conductive nanocomposite. The results showed that the CNT orientation during FFF process produces different in-layer and through-layer conductivity. ABS/CNT shows piezoresistivity and higher sensitivity with lower CNT concentrations. With 5 wt% CNT, the Gauge factor is about 5. The stiffness of 3D printed ABS could be enhanced by 100% with 3 wt% CNT but dropped with higher CNT percentages. Up to 5 wt% CNT, the increase in strength is about 25%. The fracture toughness of nanocomposites up to 3 wt% CNT is slightly higher than pure ABS and decreases after 5 wt% CNT.
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Details
- Title
- Additive manufacturing with carbon nanotube enriched acrylonitrile butadiene styrene
- Creators
- Dominic Thaler
- Contributors
- Amir Ameli (Degree Supervisor)Christof Brändli (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525372101842
- Language
- English
- Resource Type
- Thesis