Jeong-Yeol Kim

Preparation and adhesion performance of transparent acrylic pressure sensitive adhesives for touch screen panel

Transparent acrylic pressure sensitive adhesives (PSAs) comprised semi-interpenetrated structured polymer networks were prepared with different co-monomer compositions. Emphasis was placed on the effect of functional groups in the co-monomer including morpholine and tetrahydrofurane moieties in the typical acrylic PSA formulation. The synthesized acrylic PSA syrups were characterized and the optical properties of the acrylic PSA film were also examined by ultraviolet–visible spectroscopy, haze meter, and prism coupler. Acrylic PSAs exhibit high transparency in the visible wavelength region. Adhesion performance was measured by the peel strength, cohesion strength, and probe tack tests. With increasing 4-acryloyl morpholine monomer concentration in the acrylic PSAs, the peel strength, cohesion strength, and probe tack increased.

Effect of Poly(2-ethyl-2-oxazoline) on Multi-Walled Carbon Nanotubes Reinforced Poly(vinyl alcohol) Composites

The effect of poly(2-ethyl-2-oxazoline) (PEOX) as a surface modifier for multi-walled carbon nanotubes (MWCNTs) in a poly(vinyl alcohol) (PVA) composite was studied through a simple polymer wrapping and melt extrusion processes. MWCNTs were carboxylated in a reaction with HNO3, followed by mixing with 10 wt.% PEOX in ethanol to produce a MWCNT-PEOX complex. High resolution transmission electron microscopy identified a PEOX layer existing on the surface of MWCNTs. Compared with pristine MWCNTs, MWCNT-PEOX showed an improved dispersion in hydrophilic solvents such as water and ethanol. The PVA composite reinforced with 0.5 wt.% MWCNT-PEOX exhibited ~54% higher Youngs modulus than pure PVA.

The Control of Particle Size Distribution for Fabricated Alumina Nanoparticles using a Thermophoretic Separator

The control of particle size distribution of fabricated alumina nanoparticles from general alumina that has a large geometric standard deviation (GSD) is studied. A thermophoretic separator was used to control the GSD of the fabricated alumina nanoparticles. Unevaporated particles and primary particles were separated to yield a small GSD for fabricated alumina nanoparticles. The fabricated alumina nanoparticles were characterized by using a field emission scanning electron microscope and scanning mobility particle sizer. The GSD of the fabricated alumina nanoparticles was confirmed to be controlled by the thermophoretic separator. The temperature difference applied to the thermophoretic separator for the control of GSD of the fabricated alumina nanoparticles was between 79 K and 151 K. The GSD of the fabricated alumina nanoparticles was improved from 1.74 to 1.44.