Emulsions of Polyurethane for Additive Manufacturing
Open Access
- Author:
- Clair, Aaron R
- Area of Honors:
- Materials Science and Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Kwadwo Asare Osseo Asare, Thesis Supervisor
Suzanne E Mohney, Thesis Honors Advisor - Keywords:
- emulsion
polyurethane
additive manufacturing
condensed emulsion
DMF
dimethylformamide
alkane
emulsifier
3D Printing - Abstract:
- This thesis examines the characteristics of a series of specific emulsions. A 3D printer was used to attempt to create a polymeric material with a gradient of physical properties. The “ink” used was a concentrated emulsion, which was further investigated. The dispersed phase was a solution of polyurethane dissolved in dimethylformamide, and the continuous phase was a n-alkane. The emulsifier was a copolymer, which was varied between separate emulsions. The three classes of copolymers used were Polystyrene-block-Polybutadiene, Polystyrene-block-Polyisoprene, and Polystyrene-block-Poly(ethylene-ran-butylene). Emulsions were prepared through sonication. Several tests were performed: a relative solubility test and a serial graduated centrifugation test compared the stability of various emulsifiers against coalescence, validating theory. Optical microscopy was used to capture digital images of the emulsion, and then the open source image analysis program ImageJ was used to analyze droplet size as a function of sonication time and sonication power. This showed that mean droplet size decreased as time and power increased, and that droplet size distribution, normalized with respect to mean droplet size, was less dependent on these factors. Concentrated emulsion drying behavior was examined under an optical microscope, allowing qualitative descriptions of drying behavior, and emulsion drying behavior was examined under thermogravimetric analysis, allowing quantitative descriptions of drying behavior. The latter validated a simple multi-slope linear model (summarized within this thesis) for emulsion evaporation, and showed the influence of solutes in stabilizing this emulsion. These experiments allow emulsion composition to be optimized for use in 3D printing.