Yousoo Han
Study Of Foamed Thermoplastic Composites In Additive Manufacturing
Abstract: The use of thermoplastic composites in additive manufacturing has been heavily focused because of the benefits of composites in property improvements and cost saving. In this study, UMaine conducted chemical and physical foaming of the thermoplastics during the process of additive manufacturing, leading to materials saving and light weight of the products without a significant degradation of mechanical properties.
UMaine developed thermoplastic composites using a reactive polymer and wood fibers, which chemically react to each other producing water as a byproduct. The water acts like a physical foaming agent during the extrusion. The specific formulations were evaluated for its foamability in additive manufacturing with an extrusion-type of printer. The polymer of PETg was used too with a chemical foaming agent in additive manufacturing to be compared to the reactive physical foaming. The result showed the reactive physical foaming did not significantly decrease the mechanical properties of the printed objects in medium level of foamability (around 30% weight reduction). The PETg foam showed high level of foamability (over 50% weight reduction) but its mechanical properties significantly degraded. UMaine will expand the study using more various formulations with the reactive thermoplastic matrix and bio-fillers, such as wood fibers, cellulose fibers, and other plant fibers as well.
Key words; Additive manufacturing, thermoplastic composites, physical foaming, chemical foaming, bio-fillers, wood fibers, printed foamed objects
Biography:
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| 1987 - 1991 B.S. Seoul National University, Korea Major: Forest Products |
| 1991 - 1992 M.S. Graduate School of Seoul National University 1995 – 1998 University of Wisconsin-Madison Major: Forestry (Chemical modification of lignocellulosic) |
| 1998 - 2002 Ph.D. University of Wisconsin-Madison Major: Forestry (Creation of fluorine-rich hydrophobic barrier by cold plasma) |
Area of Expertise
- Production & modifications of nanocellulose
- Nanocomposites with functional/sustainable natural additives
- Environment-friendly thermoplastic composites
- Dispersion & mixing technology
- Foaming technology by chemical and physical foaming agents
- Microcellular foaming technique using super critical fluids
- Polymer processing
- Improvement of interfaces between non-compatible surfaces
- Chemical modification of natural polymers
- Polymer orientation by solid state extrusion
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