The researches in Kim's group focus on design, synthesis, characterization, and processing of facile polymers. We strive to establish the sustainable & future chemical platform by discovering & developing important polymer technologies. Several central research themes include bio-based polymers, bio-degradable polymers, polymer electrolytes & binders for post Li-ion batteries, and environmental membrane processes. The important aspect of our research is the use of modern polymer synthetic chemistries including organic synthesis, controlled polymerization, and selective polymer modification to control all aspects of macromolecular architecture.
Most current commodity polymers are being synthesized from fossil-fuel based resources, which raises several sustainability concerns. Making polymers from biomass (e.g., plant) can rectify some environmental challenges associated with petrochemical extraction/depletion and render plastic production sustainable.
By utilizing a nearly inexhaustible supply of renewable carbons in bio-resources, we aim to establish efficient and commercially competitive transformations of the abundant resources into the set of polymeric compounds. We use well-established organic chemistries and polymerization methods, especially ring-opening transesterification polymerization (ROTEP), and precisely control macromolecular architectures such as block, graft, and star polymers to achieve exquisite toughness, strength, or other practically important properties.
Accumulation of plastic waste worldwide is one emerging environmental concern. Among many potential solutions, (bio-)degradable polymers have been recognized as one possible solution. Indeed, some of degradable polymers, e.g., poly(lactide) (PLA), poly(butylene adipate terephthalate) (PBAT), have been successfully developed and commercialized. For example, PLA is being produced at about billion-kg scale per year. However, some of polymer as labeled "degradable" are only degradable under the engineering condition, not environmental condition. In addition, several macro-molecular factors such as glass transition temperature (Tg) and molar mass that are important to achieve mechanical properties are often commensurate with decreased degradability. Therefore, we challenge for designing polymers with facile degradability without
sacrificing their performance, by controlling molecular structure, architecture, and functionality. We also track their degradation with several chemical, physical, or biological ways.
Polymer Chemical Recycling
Thermosets or other crosslinked polymers including polyurethane foam have been widely used, however, most of them end up in incineration & landfill. Here, we develop chemically recyclable polymer system with several polymer chemistries. In addition, we aim to selectively recover a certain monomer from mixed plastic wastes.
for Post Rechargeable Batteries
Advanced technologies associated with rechargeable battery systems have revolutionized virtually every facet of modern world life, encompassing portable consumer electronics, electric vehicles, and grid-scale energy storage systems for nearly four decades. To meet the ever-growing demands from a variety of industries that are eager to develop next-generation batteries beyond lithium-ion batteries, still there are many scientific challenges. While the role of polymer materials in the next-generation battery systems has been underestimated, presumably because they have not been considered essential as electrode materials that generate actual capacity, polymer materials can provide indeed unlimited opportunities to afford safe and high-performance battery systems and
play an indispensable role in resolving the problematic issues.
We develop advanced polymeric materials for the post Li-ion batteries. By precisely tailoring polymer architectures, molecular weights, and functionalities, various electrochemo-mechanical properties can be optimized to cleverly exploit them as valuable candidates for organic electrode, separator, electrolyte, and binder.
Battery Wastes Upcycling
Rechargeable batteries are making our life more sustainable by replacing fossil-based energy resources. As they are extensively used, especially mobile phones and vehicles, we will encounter the exponential increase in battery wastes in the near future. There have been several efforts for the recycling of used batteries, however, most of them focus on recovering/recycling metals, such as Li, Co, Mn, and Ni. On the contrary, there are few efforts on considering organic materials in there, e.g., binder, organic electrolytes, and separator, which constitute quarter of the whole battery price. Here, we develop new upcycling technology to efficiently convert those organic waste materials into useful polymeric materials with polymer technologies. We also strive to regenerate polymeric materials that can be used in rechargeable batteries from the wastes.
Block copolymers can offer considerable industrial opportunities: micro-/nano-patterning, thermoplastic elastomers, adhesives, and porous materials. We explore the molecular aspect of the block copolymers that associated with a number of macromolecular factors such as architecture, interaction parameter, and composition. With them, we develop useful block copolymer materials for industrial applications (e.g., rubber, pressure sensitive adhesive, membrane)
Polyolefins constitute the largest part of the global plastic market because of their attractive properties. Most commodity polyolefins, such as polyethylene (PE) and polypropylene (PP), are being synthesized using gas phase monomers (e.g., ethylene, propylene) with conventional catalysts (Ziegler-Natta, metallocene, Phillips) in industrial facilities. However, the synthesis of functional polyolefins or multi-block co-polyolefins by those techniques as well as anionic polymerization is hardly accessible, making new requirement for establishing a versatile platform . Here, we develop the versatile polyolefin system, including well-defined end-functional polyolefins, based on the ring-opening metathesis polymerization (ROMP). The functional polyolefins will be used for sustainable energy efficient polymer processing, multi-barrier packaging, functional adhesives, well-defined polymer electrolytes/separators (in batteries), and highly stable polymeric binder (in batteries).