CHAPTER 5: CONCLUSIONS AND FUTURE WORK
5.2 Future Work
5.2.4 Binary Capsule Functionalization
The healing chemistry employed in this dissertation requires appropriate local stoichiometry and dispersion throughout the damage region. The local stoichiometry is dependent on appropriate mixing and dispersion of the microcapsules, even if the global stoichiometry is correct. The stoichiometry problem could be solved by surface functionalization of the microcapsules, encouraging association of the hardener with epoxy in the appropriate ratio in an A-B-A particle fashion. Such functionalization could be accomplished by silane treatment or by a urethane coupling chemistry that would join the polyurea shell of the hardener to the urea-formaldehyde shell of the epoxy resin microcapsules. If performed correctly with chemical control, A-B-A particles could be developed.
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APPENDIX A
LABVIEW TESTING PROGRAM
To perform the mechanical testing, a LabView Virtual Instrument was constructed. The wiring diagram is shown below.
APPENDIX B
AMINE MICROENCAPSULATION EXPERIMENTATION
Besides the successful TDI/Amine protocol for microencapsulation of reactive amines, other microencapsulation techniques were attempted without success. The techniques attempted are summarized below.
Gelatin-Acacia Coacervation
Ancamine K54 was suspended in brine and agitated. 1.5 g gelatin was dissolved in 3g hot water to make a sol. 5 g acacia in 20 mL water was added to the stirring Ancamine K54 solution. The gelatin was then added to form a coacervate. Capsules were not formed.
Acid Chloride Interfacial Polymerization
DEH-52 was mixed with DETA at 2:1 to create a viscous amine mixture. The mixture was added dropwise into a layered solution of xylenes over 5% adipoyl chloride in chloroform. Solid particles were formed.
Isocyanate/Acid Chloride Interfacial Polymerization
DEH-52/DETA 2:1 mixture was agitated in decalin. 0.5 g TDI in 5 g decalin was added, followed by 1.0 g adipoyl chloride in 5 g decalin. The suspension turned pink in color, and polymer was produced, but no capsules were formed.
AUTHOR’S BIOGRAPHY
David A. McIlroy was born in Columbus, Ohio, and grew up in the suburb of Upper Arlington. After high school, he attended the Massachusetts Institute of Technology in Cambridge, MA, to study Materials Science. He interned at Los Alamos National Laboratory, NM in 2001, and at TransForm Pharmaceuticals in Lexington, MA in 2002 and 2003. He earned an S.B. in Materials Science and Engineering in 2003, and worked at TransForm Pharmaceuticals until 2005. Mr. McIlroy came to the University of Illinois at Urbana-Champaign in August, 2005, and joined Prof. Nancy R. Sottos’ research group in 2006 to study the microencapsulation of amines and their application to self-healing epoxy systems. He lives with his wife, Anna, and their two children in Champaign, Illinois. After graduation, Mr. McIlroy will join Ticona Manufacturing as a Product Development Scientist in Florence, Kentucky.