Reminder of Youngman Yoo's Ph.D. Final Seminar, tomorrow, Friday, June 16, at 10:00, in ARMS 1028 From: Son, Rosemary E Sent: Thursday, June 08, 2017 1:45 PM To: 'msefaculty-list@ecn.purdue.edu' <msefaculty-list@ecn.purdue.edu>; 'msegradstudent-list@ecn.purdue.edu' <msegradstudent-list@ecn.purdue.edu>; 'msepostdoc-list@ecn.purdue.edu' <msepostdoc-list@ecn.purdue.edu> Cc: 'Youngman Yoo' <yoo59@purdue.edu>; 'yywon@purdue.edu' <yywon@purdue.edu>; Cline, Vicki L. <vicline@purdue.edu>; Son, Rosemary E <son39@purdue.edu> Subject: Seminar Reminder for Youngman Yoo's Ph.D. Final Exam, June 16, at 10:00, in ARMS 1028 "Synthesis and Characterization of Hydrophobized Cellulose Nanocrystal Enhanced Sustainable Polymer Composites via Capsule and Coat Processing" Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Synthesis and Characterization of Hydrophobized Cellulose Nanocrystal Enhanced Sustainable Polymer Composites via Capsule and Coat Processing" By Youngman Yoo Purdue MSE Ph.D. Final Exam Advisor: Professor Jeffrey P. Youngblood ABSTRACT Polymer nanocomposites show outstanding performance and bulk-processing abilities compared to conventional composites since they are recyclable, lightweight, and effective even at low filler loading. In particular, organic nanofillers with a high aspect ratio and low density are interesting because of their uniform dispersion in a polymer matrix. This feature provides excellent matrix/filler interaction for improving the thermal/mechanical properties of polymer resins, leading to lighter, cheaper, more environmentally friendly, and sustainable nanocomposites. This is why there is growing interest in sustainable cellulose materials. Nanocellulose, cellulose nanocrystals (CNCs) can be found in the natural structure of cellulose fibers. These rod-like shaped nanoparticles, which have a high aspect ratio, are nearly defect-free, and they are renewable and biocompatible. In addition, CNCs are stiffer than Kevlar and their mechanical properties are comparable to other reinforcements, even those with a low density. However, there are limitations and drawbacks in CNC based materials, including: moisture uptake/swelling, agglomeration of nanoparticles, difficulty in redispersing agglomerated particles, and their incompatibility with hydrophobic polymers. To solve these drawbacks of CNCs, it is essential to increase their hydrophobicity. One-pot synthesis for surface hydrophobization of CNCs was conducted by grafting PLA oligomers and fatty acids or their esters (biodiesel or plant oils). The key factor of this synthesis process in aqueous medium is the use of lactic acid, which is also a reactant of the hydrophobization synthesis and produces an intermediate product of polylactic acid oligomer grafted CNCs, as a solvent for the esterification of CNCs with acids or esters having a long hydrocarbon chain. It was shown that approximately one-third of all the available OH groups on the surface of CNCs were modified with the excess renewable materials which were recycled and reused as reactants in subsequent trials not only to decrease the environmental footprint of the product, but also to enhance economic feasibility. This modification level was enough to improve dispersibility in various organic solvents, such as acetonitrile, acetone, tetrahydrofuran, 1-methoxy-2-propanol, and chloroform, without damaging the structural morphology and crystallinity of hCNCs. Encapsulation technologies are widely used in a variety of applications (agrochemicals, cosmetics, food additives, ink/paints, catalysts, and pharmaceuticals); yet, protection and controlled release of core materials via conventional encapsulation methods remain relatively poor in many cases. At present, polymer composite membranes are extensively drawing attention as the upcoming alternative shell material. For the design and fabrication of mechanically robust microcapsules, polyurea-urethane (PU) composites containing hCNCs as an upcoming alternative shell material were developed through an in situ interfacial polymerization process. These nanostructured composite shells can be used to create a stable environment and allow phase change materials (PCMs) for thermal energy storage to undergo phase change without any outside influence. These microcapsules have high rigidity and maintain high strain tolerance. They also provide much better phase change and anti-osmotic behaviors, as well as, much clearer core-shell structures and higher encapsulation efficiencies than those of pure PU microcapsules. Finally, nanocomposite wood coating materials were successfully prepared by adding hCNCs to tung oil (TO). The coating process of the hCNC-TO finish using a flat paint brush or metering rod to form composite coats on various substrates (glass/steel panels or polymer film), as well as, their topography, optical properties, mechanical properties, gas permeability, and coating performance was investigated in this study. The hCNC-TO composite coatings show excellent anti-resistance, hardness, impact strength, gloss/color, gas barrier properties, and anti-weathering performance. Date: Friday, June 16, 2017 Time: 10:00 A.M. Place: ARMS 1028