Jae Heung Lee

Preparation and Characterization of Expanded Graphite Intercalation Compound/ UV-Crosslinked Acrylic Resin Pressure Sensitive Adhesives

The expanded graphite intercalated compound (xGIC)/pressure sensitive adhesives (PSAs) were prepared by syrup process and in situ process. The effects of xGIC filler on the morphology and property of acrylic resin based UV-crosslinked PSA were investigated. The xGICs showed more uniform dispersion in acrylic matrix and the degree of filler connection was more prominent in the syrup process than in situ process. The peel strength and tackiness of UV-crosslinked PSAs were strongly dependent on the amount of the filler and the peel strength decreased with increasing xGIC. The thermal conductivity of PSAs was explained in terms of filler dispersion, wetting, and matrix infiltration. The thermal conductivity of PSA was 0.46 W/mK by adding 20 wt% of xGIC, which was 287% improvement compared to the unfilled PSA. It is speculated that 2-dimensional xGIC fillers effectively formed the thermal pathway.

Self-Assembly of Carbon Nanotubes and Boron Nitride via Electrostatic Interaction for Epoxy Composites of High Thermal Conductivity and Electrical Resistivity

The self-assembled oxidized carbon nanotubes (oCNTs) with the silane functionalized hexagonal boron nitrides (oCNTs@fBN) via electrostatic interaction were used to improve the thermal conductivity while maintaining the electrical insulation properties of the epoxy composites. The oCNTs were separately immobilized on the edges of hexagonal boron nitride (hBN), which prevent oCNTs from continuously contacting with each other. The thermal conductivity and volume resistivity of oCNTs@fBN filler loaded epoxy composites were measured and compared with the epoxy composites with a filler of hBN, a mixed filler of oCNTs, and silane functionalized hBN (fBN). The thermal conductivity of the epoxy composites containing 20 wt% of oCNTs@fBN10 was 1.26 W·m-1·K-1, which is higher than 600% compared to that of neat epoxy and the volume resistivity of the epoxy composites was in an insulation region even at high content of oCNTs@fBN filler. The significant improvement in thermal conductivity was attributed to the formation of linkages between oCNTs and fBN and the good compatibility of oCNTs@fBN in the epoxy matrix.