Papers by Author: Young Chul Lee

Abstract: Novel hot chamber rheo-diecasting process has been successfully developed. It requires no additional processing equipment except commonly used hot chamber diecasting machine, no molten metal control like grain refinement procedure and no additional cycling time to produce slurry-on-demand. Additionally, it could lower molten metal temperature in a furnace. Process concept of novel hot chamber rheo-diecasting is simply based on the paradigm shift from HOW to WHERE for producing slurry-on-demand. This paper will demonstrate the possibility to achieve slurry-on-demand by novel hot chamber rheo-diecasting and the advantages for 3Cs applications.

Abstract: Novel In-mold rheocasting, which can satisfy all the development direction of rheocasting, has been successfully developed. In-mold rheocasting requires no additional processing equipment except diecasting machine, no grain refinement procedure and no additional cycling time to produce slurry-on-demand. Process concept of In-mold rheocasting is simply based on the paradigm shift from HOW to WHERE for producing slurry-on-demand and the shift from obtaining PERFECT solid globules to casting OPTIMUM products. Optimum external field can be generated in mold, that is, in die cavity exactly around biscuit. This paper will demonstrate the possibility to achieve slurry-on-demand by In-mold rheocasting and some commercial products.

Abstract: Nanostructured modification of polymers has opened up new perspective for multifunctional materials. Carbon-nanotubes have the potential to increase the conductivity of their composite, with improved or retaining mechanical performance. This study focuses on the evaluation of the thermal and electrical conductivities of carbonnanotube filled alkyd resins for steel coatings. Polymer/Carbon-nanotube nanocomposites have been prepared by mixing commercial multiwall carbon-nanotubes with alkyd resins and by curing. The thermal and electrical conductivities of carbon-nanotubes filled nanocomposite was found to be increased comparing with the original resin without any fillers or with the resin with carbon-black or carbon-nanofiber.

Abstract: Epoxy/clay nanocomposites have been prepared using montmorillonite (MMT) ionexchanged with various organic cations ; hexadecyltributyl phosphonium ion, octadecyltrimethyl ammonium ion, methyl tallow bis-2-hydroxyethyl ammonium ion and dimethyl hydrogenatedtallow (2-ethylhexyl) ammonium ion. The resulting nanocomposites were found to show exfoliated clay structure by using transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The flame retarding property of 5wt% clay/epoxy nanocomposites was found to be enhanced when compared with that of the original epoxy without clay.