Microscopy, Chemistry, Thermal Analysis, and Mechanical ......Additive Manufacturing of Various Polymers: Microscopy, Chemistry, Thermal Analysis, and Mechanical Properties Yukai Tomsovic1,

Additive Manufacturing of Various Polymers: Microscopy, Chemistry, Thermal Analysis, and Mechanical

Properties

Yukai Tomsovic1, Colin Moore2, (Mentors: Austin Ngo, Eli Darby, Michael Roulier, Pejun Hou, Yuan Li) 3

1 West High School, 2 Sevier County High School, 3 University of Tennessee, Knoxville

ABSTRACTSamples of various polymer filaments and fill densities were 3D printed. Microscopy and chemical and thermal analysis were used to study the microstructure and composition of the samples. Tensile testing was then carried out to study the effect of different materials and densities on mechanical properties.

Additive manufacturing builds objects by adding layer upon layer. Specifically, this project used fused deposition modelling (FDM). In FDM, a thermoplastic filament is melted onto a platform and solidifies as it cools.

1. SYNTHESIS & PROCESSING

Fig 1.2: 25%, 50%, 75%, and 100% fill density dogbones

25 % 50 % 75 % 100 %

Fig 1.1: CopperFill, ABS, BambooFill, & Neat PLA dogbones

OBJECTIVES

4. PERFORMANCE

3. COMPOSITION & MICROSTRUCTURE

Mechanical properties of different materials and densities were analyzed. In Fig 2.2, PLA has the highest ultimate tensile strength (UTS) and yield strength (YS) while copperFill is the weakest but has the highest elongation. The varying densities shared a positive linear relationship with the mechanical properties. The 50% has very similar performance to the 25%: therefore it would be more cost effective to print at 25% rather than 50%.

SUMMARY REFERENCES

This work was supported primarily by the ERC Programof the National Science Foundation and DOE under NSF Award Number EEC-1041877.

Fig 3.6: Elongation vs fill density

Fig 3.7: Yield strength vs fill density Fig 3.8: Ultimate tensile strength vs fill density

Fig 3.5: Young’s Modulus vs fill density

Fig 2.4: Optical micrograph of CopperFill

Fig 2.1: 21% PLA Fig 2.2: 47% PLA Fig 2.3: 73% PLA

2. PROPERTIESNeat polylactic acid (PLA) is used in cups, bottles, and packaging. Acrylonitrile-butadiene-styrene (ABS) is used for LEGOs, cars, and electrical equipment. CopperFill is conductive. BambooFill is only for cosmetic purposes.

Using imageJ the actual fill densities of the Neat PLA samples were measured based on the area of the unit cell outlined in orange.

Energy Dispersive Spectroscopy (EDS) can determine the composition of a material by measuring the energy of x-rays emitted by electrons as they move down energy levels. The EDS identified high concentrations of carbon in the darker region and an increase in copper concentration across the white particle.

Thermogravimetric analysis (TGA) measures the change in mass when temperature is increased at a constant rate. About 80 wt.% of the filament remained after heating, so the CopperFill filament consisted of about 80% copper by weight.

Fig 3.2: Stress-Strain curve of different materials

Fig 3.1: Fill Density Stress-Strain Curve

Fig 3.3: Yield Strength v UTS Fig 3.4: Young’s Modulus of Varying Material

• Based on YS and UTS, in order from strongest to weakest, PLA, ABS, BambooFill, and CopperFill.

• Based on elongation, in order of ductility from most to least, CopperFill, ABS, BambooFill, and PLA.

• An increase in fill density resulted in an increase in Young’s modulus, elongation, YS, and UTS.

• EDS and TGA showed that the CopperFill filament had approximately 80% copper by weight.

"ABS." ABS - RepRapWiki. N.p., 15 Apr. 2016. Web. 15 June 2017."AM Basics." AdditiveManufacturing.com. Amazing AM, LLC, n.d. Web. 12 June 2017.National Research Council. 2005. Globalization of Materials R&D: Time for a National

Strategy. Washington, DC: The National Academies Press. doi:https://doi.org/10.17226/11395.

"PLA." PLA - RepRapWiki. N.p., 27 Dec. 2016. Web. 15 June 2017."Scanning Electron Microscopy (SEM)." Warwick Faculty of Science. Warwick

University, 11 May 2010. Web. 14 June 2017.

Fig 2.7: CopperFill at 750x magnification

● Use FDM to manufacture tensile samples● Perform qualitative/quantitative microscopy to determine chemistry

and fill densities ● Evaluate the amount of copper in CopperFill through thermal

analysis● Analyze mechanical properties of different materials and as a

function of fill density

Fig 2.8: Element composition

100 μm

331.40 °C

19.96%(10.82 mg)W

eigh

t (%

)

Temperature (°C)

Fig 2.5: Optical micrograph of BambooFill

Fig 2.6: Optical micrograph of ABS