Papers by Author: Do Yeon Jung

Abstract: The delamination and fibers pull out have been the main factors failure application of natural fibers in various engineering fields. To address these problems, particles reinforced composites are the promising candidate. The present paper investigates on vegetal particles (date palm seed particles/DPSp) and applies it as composites material reinforced unsaturated polyester (USP). The influence of alkali treatment on the surface morphology and structure of DPSp was investigated. They investigated by SEM and Energy Dispersive Spectroscopy (EDS) mapping. The water absorption results showed directly proportion with the particles loading as the relative increases were 0.645% and 7.345% for 10 wt% and 40 wt% of DPSp content, respectively. In addition, the water absorption ability of the composites showed low value comparing with many natural fibers. In addition, the fracture toughness of the composites was studied. Overall, addition of the proposed DPSp particles may be opens a new avenue to exploit the utilized natural cheap material to produce a green composite.

Abstract: Abstract. In present study, the effect of irradiation along with applied load and three periods on the ultraviolet (UV) aging of the polycarbonate polymer was investigated by observing the changes in the mechanical properties. Dog bone specimens of polycarbonate were subjected to different test conditions namely in the amount of applied load and the variation in exposure time to the UV lamp. The results showed that, with a constant applied load of 1kN, increase in the exposure time in UV radiation caused the mechanical properties to relatively increase at first and decrease gradually afterwards. However, for constant exposure time, the tensile strength showed much decrease with increase in applied load. For the test conducted at higher applied load of 3kN, the mechanical properties of material relatively improves in a drastic manner for the higher exposure time. It was inferred that the increase in applied load has a crucial role in the UV aging of polycarbonate for the given exposure time. Moreover, the morphology of the fracture area under different test conditions was observed by Scanning Electron Microscope (SEM).